I have been threatened at school?

[FyreSkag]

Back 1 and a half years ago I posted on someones picture on facebook saying bad things about him because he is mean to everybody. and now for 1 and a half years they have been talking about attacking me. Their serious. I can see it. Theres a group of dumb preps at school who want to attack me. Im wimpy and skinny so theres nothing i can do to protect myself. They are big and buff and they would kick my ass. I didnt want this to happen and now im living in fear at school. should i call the police and tell them that someone threatend to attack me? I dont know what to do please help.