I know this wouldn't make a moving feel-good movie, but . . .
there's "being yourself" and there's being yourself.
One involves keeping your own style but generally finding socially acceptable ways to display it; the other is aggressively saying "If you don't like me exactly
as I want to be, F you." The former will (eventually) help you find friends; the latter not so much. Examine what it is that makes you unpopular and try to make an unbiased judgement about how important that element is to you - is your right to insert broadway show tunes into conversation whenever possible a part of "who you are" you need to cherish, or is it a habit you could tone down if it's keeping you from making friends?
Along the same lines - in high school, your friends define your social standing. In the rest of the life, they define your quality of life - if you don't have friends you can trust, you won't have an outlet to find a significant other, let off steam, cry on someone's shoulder, etc. And throughout life but especially
in high school, you and your friends are kind of a package deal when it comes to meeting new people. It is absolutely your choice if you want to be friends with the emo/theater/jock/whatever crowd, but that choice limits the other friends you can make. Some people seem to naturally be able to straddle the clique divides, but odds are you aren't one of them
Long story short, if your social group is causing you more stress than enjoyment and you didn't really want to be spending time with them anyway, creating some distance can actually help your social life in the long run.
All that said, it also comes down to luck
I was lucky - the popular girls my year were actually pretty nice, good students, and were in choir with me for years. I was never super-popular but they accepted me for my singing voice - and my year, being a good student wasn't a bad thing because they were good students too. (All three of the most popular girls are now elementary school teachers, actually, and I bet they're fantastic at it.) My sister was a year behind me, and it was a totally different story - the popular girls her year were cheerleaders without a whole lot else going for them, and they had a "mean girls" clique straight out of Hollywood. My sister's best friend was the biggest social reject in the school, and since my sister refused to sever that friendship, her social life suffered a lot. I think if she had been in my year it wouldn't have been anywhere near as much of a big deal.