Dude, I kno exactly how you feel. My situation is similar: I am in a private school, in honors classes, but Im pretty athletic and decently popular, so if you were to pick the kid who plays pokemon out of a crowd that i was in, you would never, ever pick me. two of my friends kno i play, and share my interest in the game, and these are kids that also keep it in secret and you would never guess played. Its quite funny, 2 of us were on the football team and the other is like a tennis prodidy, but like we kept it in secret and noone found out/ told anyone else about what went down. We refered to it as "the secret club" when talking about it and noone knew what the hell we were talking about loll. But eventually one of my friends decided to focus more on oblivion on his 360 during his free time, saying hed never catch up and be as good as me and my other friend. So my friend and I had quite a few battles (i beat him every time, but this was before we knew about smogon, evs, ivs etc.) but as I did more research online about how to become better, learning the ropes and such, my friend was a little slower in doing so. I eventually surpassed him by a huge amount, I actually don't think he has a competitve eved team, never mind IV oriented. But our secret never got out, which is quite amazing, howver we all knew if word got out wed be wrecked by everyone else, similar to your story. Dude, i really dont know how to give you advice except to just laugh at any pokemon joke and to act like it doesnt affect you, that way people will lay off you and eventually forget about it. Its amazing how people dont kno how competitve and fun pokemon could be.. they dont know what their missing out on!
EDIT: this was last year, when I was a freshman. One of these friends left my school to go to another one, and I dont talk to the other friend about Pokemon anymore. I guess I am the only one who got to the next level..