what does it mean when your crush doesn't like you but uses you for sexual pleasure? i feel betrayed?

Okay so first off im not in a relationship with this guy and we've never been togther. I used to have a crush on him for 2 years. Basically he used to be nice to me. We were never friends we were more acquaintances and he would talk to me when we were around my guy friend in like 9th grade. We are now going to be seniors and these past 2 years he has been verbally abusive to me. He always talks about me badly behind my back telling people im creepy and weird and annoying when i dont do anything. he blames me and says im the one who won't "leave him alone." and when i confront him he lies to me. when we were in 11th grade he told the new and upcoming 9th graders that im weird and that they shouldn't talk to me. i hadn't even done anything for him to say this. but he also stares me down like its creepy. he stares at me and smiles sometimes he glares at me. one time my friend told me he almost tripped up the bleacher stairs to stare at me. and when had a class together 1st semester of 11th grade and he would like stare me down and then he would get up and go to the bathroom and before he left he would look at me as he was going out the door and then he'd be gone for like 5 minutes. then he came back and the first thing he would look at was me. one day he did this and he stood up and stared me down and then i looked at him and i looked down and he had a bulge in his pants and i looked back up at him and he gave me this creepy smile. I also had a dream of him beating me. Advice?