My family thinks i'm an idiot.

I go to college, work a full time job, I'm in the Army Reserves and I am close to getting a degree. I'm not on drugs and I don't have kids yet, I'm working on my career. My cousins all have children they can't support, have multiple convictions, drink and party nonstop and give almost no fucks. I am the loser of the family.

Some families just suck. It's the way of the world.

The first piece of advice I could think of is for you to try and feel better about yourself. You have your reasons to; your accomplishments may not seem important to your family (although it could just be your perception of how they perceive you) because they might value different things than you. There's nothing wrong with it and I'm one of those who values education and schooling more than working in jobs that don't require you to use your knowledge. I can't understand though why you can't seem to get a job. I tend to think you haven't tried hard enough, or looked in the right places, but that's just a thought. You might be looking for work that is not exactly compatible with your natural abilities. As for your family's expectations, like I said, it's possible that you prize different things so, if that is the case, you'll just have to accept it and create your own set of standards for what being successful means and move on, knowing that you *are* different than them and that it's absolutely normal.

My heart goes out to you, friend, not only because I can relate, but because it sounds like your family is causing you a lot of pain and that's just not okay.
First of all, I have to put this out there: intelligence is not a marker of a person's worth. You sound smart and hardworking to me (3.8 GPA, what's up!), but even people who are less intelligent than average deserve love, acceptance, and respect. They can still contribute to society, have friends, fall in love, whatever. Again, you sound smart to me, but I had to point this out.
Second of all, you may not be getting hired because those places think of you as sort of overqualified (read: too smart) and assume that you'll think you're better than that workplace and not be a good employee. Try applying for low-level jobs at your local library, or maybe doing light office work for one of your friends' parents. You'll probably be happier there, anyway. If even those options don't work, you can always tutor people at your school - with your grades, I'm sure people would be happy to pay you for your help.
I saved the most important for last - third of all, your family doesn't sound supportive, accepting, or even particularly caring. It's one thing to think someone is an idiot, and another to treat them unkindly for it, or refuse to let them change your mind. Your GPA demonstrates that you're at least of average intelligence, probably a little higher, and certainly not stupid! Even if you were stupid, your GPA indicates that you work hard to overcome it - which is even better than being naturally smart!
Your attitude sounds appropriate to me. Your family's does not.
I can relate because my father suffers from extreme bipolar disorder, and for most of my life he was unfairly exacting and demanding. I would bring home a test with a 98% percent and he would ask me what happened to the other two. He treated me this way from birth, which I think is one reason I'm so anxious and have trouble valuing my successes (I have a 3.7 GPA and I'm in college, which is waaaay different than a 3.7 in high school). When I told him that my book was going to be published, he nodded and said, "That's good." When I told him it had won an award, he said, neutrally, "Great." That's it. I was sixteen when my book was published.
Recently, however, my father began taking medication for his bipolar disorder, along with working on changing his thoughts and managing his feelings, and it has improved his attitude beyond belief. He is now supportive and encouraging.
I don't tell you this because I think your family is mentally ill or can be fixed with a pill. I say it to prove that sometimes, people do change their opinions, so don't give up all hope.
On the other hand, I have two younger sisters who both hate my guts and utterly disregard me as a human being. I have some mental health demons of my own, which Dad, back in his bipole days, taught them was basically a weakness and a character flaw. He pretty much trained them to treat me like a loser.
Their favorite thing to call me is a freak, but they also like psycho, lunatic, idiot, moron, crybaby, spineless, weakling, loser, pathetic . . . you get the idea. They tell me that I'm never going to accomplish anything, that our dad has no faith in us, that I'm crazy, that no one will ever love me because I'm so crazy, etc. They demand that I help them with whatever they need, and I do, because I want top be a good sister.
It goes way above and beyond normal sibling crap. It's abusive behavior. When we were all in high school, school counselors actually got involved in our family because they were "concerned" by the "abnormal and harmful attitude" my sisters seemed to have regarding me, and that their behavior and speech to me was "damaging and unacceptable".
So yes, as an award-winning author college student pulling a 3.7 GPA, working on another publication, thinking about medical school, and battling mental health problems, whose family STILL says I will fail and never have friends or a boyfriend, I definitely feel your pain.
What you have to do is ignore them. And I know it's hard. These people are supposed to love you, and you love them, which means that whatever they say is going to get to you. It will make you sad and make you doubt yourself. It will hurt. You will cry. You will feel alone.
But you look at yourself in the mirror and say, "I am beautiful. I am smart. I work hard. I am funny. I have friends. I am brave. I am strong in the face of those who would stop me. I can do anything I want. I am POWERFUL."
Say it out loud. Say it over and over until you believe it. Say it in your head when they're talking to you, so you hear yourself and not them. Write it inside your notebooks, write it on the insides of your arms, write it on your mirror in dry-erase marker. This is how you fight back, how you do not let them win, let them beat you into thinking you are nothing. And if anyone sees it and tries to make you feel stupid about it, LIE, and say three little words: "I. Don't. Care."
Maybe eventually it will be true for both of us.
You are brave and strong just to live your life every day when people don't believe in you. You are smart. You are worth love and respect. You have the ability to be great. Now fight back.

My immediate family has been treating me like an idiot or someone who is mentally retarded (no offence), for some reason too. I think it is because I didn't meet their linear expectations to a T. It might also be because I want to do different things with my life and take different career/education paths that they don't agree with. None of it makes any sense... I am trying to better myself but, they keep putting me down and highlighting constantly on my faults. (Etc.) I think that we should use this as fuel to better ourselves and prove them wrong. Pick a person(s) that you would want to make proud. It doesn't have to be a family member. Then when you become a success, you can look back and watch your family wallow in their negativity. Don't allow them to ride on your successes. Don't pity them either. They are dead to you.

You entire family sounds immature. You are the only rational and mature one. Don't let them bring you down.

What do you want to do with your life?

When you say you always did anything to make people smile, I wonder if your family treats you as a scapegoat to make themselves feel better. That is inappropriate. That is weak and that is mean. Are there people in your life who think you are great just the way you are? That's your real family. Be with those people as much as you can. If you can, I would start looking for interesting places to intern or get experience for a real job later on. Find out what you are good at and what makes you happy. I hope that with positive feedback you get from others,you can put these cruel people in the rear view mirror of your mind!

I felt a bit touched when i was reading this, two advice, firstly u a smart don't let them pull u down secondly have faith in your self

Yeah, it's normal.