Why do I feel so different form everyone else if I'm ordinary?

When I was younger, I incessantly felt like I was incredibly different from everyone-- I had different interests and I wasn't absorbed in culture and music that others were. People weren't outright mean to me, but it was pretty obvious to me as a child that other girls weren't interested in befriending me at all. As time passed, I slowly became less and less of an individual and conformed to the mold that people of my age and sex are supposed to fill.

I recently moved to a new school in a new state. No one knew who I was, so I could blend in and be just like everyone else without anyone thinking of me as that weird kid they knew growing up who tried to stop being weird. And I guess I fit in now because the type of people that wouldn't have talked to me are now interested in being my friend. I enjoy their company, of course, but I can't help but feel they still secretly think I'm weird or misfit or what have you.

Why would I feel this way? Someone please help because I can't put up with this uneasiness much longer. What the hell is wrong with me?