I almost comited schoolshoting and i need help

As you mentioned, you're going to see a psychologists, and I think that's better than looking for answers on this site.
I assume you're underage, and if you already pointed a meeting, your parents probably know about this. Unless the laws where you live state otherwise. In case you haven't, talk to them.
That's the only advice I can give.

Dude you need to stop thinking about this bullshit and just pay attention in school, you can barely string a coherent sentence together.

Just remember that when you have hit rock bottom, things will get better. There are people who care about you, and they will help you if you need. Seeing a psychologist is a good idea though, because they are good when you are in a time of stress.

Well, all is not lost, and whether you believe in God or not obviously someone up there likes you, because you were able to snap out of it, and realize how messed up your thinking was in that moment. I want to congratulate you on seeking out help, because there are so many people who don't seek help, and go on to do awful things. I'm very glad that you will be going to see a psychologist soon! I'm certainly not a professional so I can't even begin to tell you why you had the urge to do those things. It's good that you are in touch with your feelings enough to recognize what you were feeling, and that you have enough of a moral compass to realize it's wrong. I wish you all the best in your therapy.

All these people on this site are gonna tell you the same shit. Study, think of something else, go see someone, blah blah blah. Now I’m not telling you to shoot up a school by no means, but honestly I see why you hate the world and the people in it. Especially our generation. We live in shity times. You aren’t the bad person here, it’s the people around you. The world is full of dip-shits with they’re heads in clouds. If you go to psychologist they are going to tell you that you are the one who needs to change, and they probably will probably give you pills. What I suggest is... meditation. learning about the energy around you and how to change your life by your self with out changing who you are to appease the world. Do this and you will be happy about the people around you and the world. You can change your whole world.

Your a pussy and killing kids is horrible lol stop thinking about shit like that ! If someone is bothering you be a man and punch them in the face!!!! Don’t take shit from anyone who fucks with kid but don’t go killing anyone in the end you will only fuck you life up !!! Those are someone’s kids and they have parents who care about them !! You have no right to take anyone’s life in your hands !!! You kids need to tuff in up and learn to fists fight !! You kill my kids and I will kill your hole family and your dog !!! Kids are mean and everyone goes through shit as a kid !!! Get over it and find an outlet for your anger!!!!

People can really suck sometimes. Ignore the crappy people and cherish your parents who love you. Not everyone has supportive parents! You don't even have to tell your parents how you're feeling, just spend more time with them and you will feel less alone.

Good you realised that you were about ruining your life and many others before it was too late. It's a good idea to talk about it to someone who might help you better than us here.

hope your better soon