Was I wrong to do this?

A kid in my class named Greg was being a HUGE jerk like always, but this time it was to people I like. He was calling them stupid and names I wont say on here so it doesn't get deleted, and then he was throwing things. He threw a book at my friend Silas and then a full water bottle at my head. (not the little flimsy kind, the hard reusable ones.) He has done other things to me that were mean, and today my patience just snapped and I banged his head against a locker!!!!! Was that wrong? I do have anger problems and have broken my hand from hitting walls and things in anger. I didn't seriously injure him, but I think it hurt. But he hurt me and I'm a girl. A fragile, gentle girl. lol.