cold faced girl

I kind of hate the social aspect of going to school more & more as the semesters go by. The faces in my classes become more familiar & less friendly. I don't really understand why people pretend that they don't know who someone is when they definitely do or especially why you'd treat a person like they are invisible when you've seen them time & again. Maybe it's my fault because everyone else in the classes are friends with each other & just not me. Sometimes I think they must think I'm a cold faced girl or something but that's not who I really am. Have I created this in school persona for myself? How & why did I do this?