I’m so, so sorry you were bullied so badly. What you are feeling is not unusual but it isn’t helpful.
Let me explain: Often people who are victimized come to the conclusion that the only way to avoid being a victim is to be a victimizer. It’s as if your unconscious mind has only 2 positions on a switch: Either I’m a victim or I can be powerful and avoid being a victim by being a worse bully than the bullies.
Again, this isn’t unusual. But it does mean that the bullies of the world “win” because your only alternative to being bullied is to be one of them.
What therapy offers is help finding a third position for that switch. In therapy, you will learn how to cope with your understandable anger and how to use it effectively. No, it won’t stop bullies from trying to bully. (They need therapy of their own to deal with the insecurities that cause a person to bully.) But a therapist can help you learn how to take care of yourself and others without becoming the very kind of person you hate.
For that reason, I hope you will talk to your school guidance counselor about how to find a therapist who specializes in working wtih teens. You deserve the help. You need the help before you do something you will truly regret.
I wish you well.