Bullied for being a Christian?

I'm 19. I'm in college. I have very strict Christian morals. I don't drink, do drugs, have sex, party, or break the law. Pretty much what other college students do. I'm always being asked to go to a party or something. I tell them that I can't go. They just laugh at me & call me a "Jesus Freak". I was told that noone gets bullied in college, but I guess they were wrong. Also, I don't date. I've had girls come up to talk to me. How do I shoo them away in a polite way? I'm not even good-looking. here is a photo of me