Is it normal to hate my own mother?

This may be long.

Hello, I am currently 20 years old and as of right now, I can't stand to be around my mother. Not only is she annoying, belittling, and a constant bully to me day and night; the woman just makes me absolutely miserable. Every time, I am around her I feel my happiness just fading away, depressed, and then a heavy lump begins to form in my chest. Normally, I used to be happy when my mother was around me when I was younger but ever since these changes with her; I find myself pushing her away even more. However, its not like the woman gives me privacy of my own, so that could be a key factor too. Here are a number of things that she does to make me upset.

1.) Calls me names and insults me every chance that she gets

I can't even count the amount of times she has insulted me even if I do or don't do something wrong. For some reason, she just loves to torture me and belittle me by calling me names such as "idiot, stupid, devil, demon, good for nothing," and far much worst than that. In a roundabout way, she has called me "bitch" to my face. I have told her countless times to stop and I have tried to confront about this many times before. When I try to talk to her about this, I take her to a room with her and I alone and try my best to talk calmly to her and convey out my feelings to her how her insulting me makes me upset, and angry on the inside. But she just retaliates by saying "I do not care how you feel, I am the mother and you just have to deal with it. Do not tell me what to say in my own home"
She doesn't bother to listen to what I have to say and does whatever she wants. It has gotten so bad that I have started to retaliate back by starting to say mean comments to her just to hurt her emotionally just so she can understand how I feel when she does it to me. When this happens, she will not speak to me for a few days and then later on take her build up anger out on me and then say that I am the bad guy.

She does the same thing even when I try to be nice to her. A few weeks ago, I offered to drive over to her business to go get some documents that she needed to be read and then signed immediately by her clients while she was away on a business trip in Denver, Colorado. I did that for her just for her as a attempt to relieve some of the stress that was building up inside of her. In all honesty, I did not want to do it and I just did it to be nice. As I was reading to her, she just goes berserks and starts screaming at me for no reason that I just started to break out crying. Once I did that, she just hung up the phone and left me as I was just sobbing. Then few moments later, she called one of her employees to see how if I was still doing what I was suppose to do. I didn't bother to response to the employee because I was just so upset and neither did the employee asked if I was okay; I just knew she was snickering at me because she has seen me and my mom argue countless of times before and she has not done anything to help. So, I just went home in tears, sand just left the documents on the desk. As soon as she got home, she punishes me for this and then tells me to apologize. I honestly do not see how I am wrong or need to apologize when I was trying my best to help her out. She even texted me insults on the day this had happened.

2.) Puts my dreams down

I am currently a college student that is going for a Bachelor in Science for Biology and hopefully be able to attend medical school once I graduate. I always wanted to become a doctor ever since I was little and I will admit my mom has been there to encourage me to go for my dreams. However, ever since I started college she has been putting that dream down a lot lately and thats one of the many reasons I am mad and just can't stand her. She even told me over the phone that "I am so tempted to let you fail towards medical school just to teach you a hard lesson" I do not know how anyone can just deal with that and just let that go. She acts as if its nothing important. I have told her before that volunteering and shadowing hours are also requirements for medical school as well, but she acts as if she doesn't care. She even told me straight to my face that the doctors that Im currently shadowing "They do not care" Even if its true or not, I still think saying something like that stings more than rubbing salt into a open wound. My grades weren't so good during my freshman year but they are greatly improving now, I did extremely well during sophomore year and now I am going into Junior year. I think I can do it, but I do not know why she thinks that I can't. (She makes it seems like I can't...)

She just doesn't seem supportive at all especially at the time I actually need her to be... I have also told her that I feel as though I am behind and won't graduate on time. She doesn't seem like that she cares at all. She refuses that I take summer courses to catch up.

3.) She always laugh at me when I cry

Every time I cry, she always end up either laughing in my face, slaps me or once again insults me until I have lost it. She even occasionally throw things at me like a spoon or even a can of hairspray one time. I seriously do not know whats wrong with her. Im so tempting to inform a therapist at my school about this. I really cant take this anymore and I seriously do not care what happens to her. If she died tomorrow, I would be overjoyed.

I also really want to know what causes a parent to act this way towards their own child? My brother never gets this type of treatment and he is always portrayed as the good one.

I would love to get away from her and I do have a job but I do not make enough to be able to afford a apartment of my own. Also, I rely on her income to help pay for my tuition...so I really in a bind here...