Help?

Well, Ты are doing something right already... Asking for help. Go to a therapist and tell someone Ты trust about this. And please dont cut yourself. It wont help you

First of all, cutting won't help you. Even though Ты hurt other people, doesn't mean Ты have to hurt yourself.
Also, Ты need to act еще positive. See the good side of things. It will change how people act around Ты and Ты will find them less annoying.

I had a similar problem when I was younger, and I liked hurting people just to see their reaction. I guess I was lucky and grew out of it because now I can't even imagine hurting anybody.
It sounds like Ты have Sadism, which just means enjoying pain. But it is good that Ты are asking for help, it means that Ты want to stop and Ты know it's not right.

Please don't cut yourself. Ты need to go to an adult - a therapist, the school nurse, your parents. They'll be able to help you.