HELP! Being bullied...?

There are these girls that I have to llok at everyday because they are the clroom right in front of mine. One of them literally looks like a rat and the other one is a butch looking girl. I used to be there best friends until I stopped doing drugs and now everytime i get out of my clroom they are waiting for me to say stuff to me like anorexic and nasty and a as ***** and worse things. One of them literally beats everyone up but I know they wont touch me because the dean said they would be expelled but i dont know why there words bother me i really dont. ANY ADVICE on to stop being nervous about seeing them? or any advice on how to make them stop?