Is this normal? why do i feel like this? i'll appreciate any advice?

Every-time i'm at school, if i hear someone near me laugh i allways...ume that there laughing at me all the time, this may sound slightly insane (in fact it will) but today i was late for my cl so the corridors were empty but for two girls walking behind me and i slowed down let them p me and well i almost....almost tried to...well...kill them. I just had the picture of smashing their heads o the walls ad laugh at them. Pls, i dont want to end up doing something...that i shouln't so what on earth should i do?!?!