We've never had sex before, I'm not a virgin but I mean I've never had sex with this girl before. We've been dating since summer, last year so we've been together for almost 2 years. Last night we had sex, it was crazy and very passionate and it was amazing. But now she won't answer my calls or texts, she keeps avoiding me on campus and says "Oh, I've just been so busy, I'll call you later." and now she keeps being all giggly and over excited around this other boy. I'm strong but I'm not like athletic or a bodybuilder, I have some muscles and a great body but he's a size of a rugby player, has tattoos and piercings and he's funnier than I am. I'm very worried. I feel used. Me & my girlfriend have been waiting for the right and last night we went crazy for each other but then afterwards, she kisses me on the cheek and gets up and leaves. She claims she had to be up early. I haven't had any messages from her since. What do you think is happening?