My "friends" Are Excluding Me

I have friends that I live with on the university campus housing. It's people that live on my floor. I've lived with them for 4 months or so now. I think we've had a good relationship in the first semester and now we're beginning our second semesters and things have changed. I've actually been more quiet than normal because I'm actually trying to study more (I partly found people loud and kind of ignored them). And today they signed up for a group activity event and didnt even ask me if I was intereted. This was very sad for me because a lot of times we do things together as a floor group or something. However it's not even that that I am mad about. On top of not asking me, they were trying to hide it..not tell me at all. I am really disappointed with them and I feel like I've lost my friends and I couldnt treat them the same as before. I'm not acting like I am mad or anything because I'm not the type to start things with people. I really dont know what to do and I cant sleep because I keep thinking about it.. Help please!
An Ep User An EP User
Jan 8, 2013