Am I going to far over a slap?

No youre not overreacting. I knew a girl who was a total b*tch and she could get away with it because of "problems". We all have effing problems but we dont all go acting like bullys. Ffs. Yes do the police thing if that fails then punch her in the face, seriously, do it as hard as you can and then if teachers question you over it and get you in trouble just make up some sh*t about you having so-called "problems". Maybe spread a bad rumour or two about her too x). Dont let her get away with it, though.