Help me my friends r goin crazy Plz Help?

My friends r starting to be jerks i mean i am a small bully but i am to deffened myself but now there goin insane over it braken kids bones cutting them beatin them up what should i do to stop it i tried once and he hit me in the face and broke my nose help me what do i do!?!?!?!?!?!?!?!