I got in a fight Friday and I'm thinking of what would happen. Help?

So this chick and I have had problems since 2nd grade she has always tried getting me in trouble and snitching. So were in 7th now and she she was still messing with me but it only got worse she was talking trash starting rumors and we are like in the 2nd week of school. But she was acting like she was my friend earlier that morning but then my best friend hands me this note she wrote about me just a few minutes before. So i asked the girl did she write it and she said yeah, so I said that is just so fake to do that. So she calls me a bit*h so I slammed her head against the locker and I was punching her and she didnt hit me but one time and it was a cheap shot cause the teacher had me and the other teacher let go of her. So everybody saying I won and stuff. But see last year she went to another school and got beat up there twice and so her mom moved her back to our school. This girl is in my homeroom cl and her locker is directly next to mine. So how should I react when I see her? What if she tries to fight me again? She's probably going back to school before me since I got the first hit, so what if she tries starting another set of rumors about me. Like everyone hates her and she thinks everyone loves her. When the fight was over people were like omg you beat her ***, and her check bone was bruised or something. helpppp me!!!!!!!!!