Kid, nobody feels like they belong at your age. I certainly didn't. Still don't. Only difference now is I don't really care if I fit in. I mean, look at how boring most "average" people are! Are you sure you even want to be one of those guys?
Really, I think you should count yourself fortunate that your reasons for feeling that way are due to the kind of video games you play. I mean, try to imagine how difficult it would be to go through school being a Muslim, or gay, or blind, or living in extreme poverty, or having three heads or something.
I had a friend when I was your age who had three heads, and I saw how difficult it was for him to fit in (much less find t-shirts that fit).
Anyway, I don't mean to disparage you, but if the type of video games you play is your biggest problem in life, then you probably have it pretty good. And it's patently obvious that, by playing GalCiv2, you are part of the most intelligent, best-looking, coolest group of people on the planet, if not the whole universe!