Teen years are tough, I'll admit it. I was the shortest and scrawniest kid in school who always got picked-on until junior year (when I got into my first fight in high school). Even during senior year I was still small and felt stupid and hopeless. That was 10 years ago. I look at myself now and realize I'm looking way better now and I'm more assertive, motivated, and success-driven than ever.
Matter of fact, I went to my high school reunion in November to find out that the douchebags that picked on me now have dead-end jobs, unplanned kids, and look older and more haggard than their actual age (try looking at a 28-year-old that's completely bald and morbidly obese while keeping straight face). As for the hot chicks that turned me down at school, they're the female equivalent of the douches (maybe even bald) trying to talk to me, even they know that now I wouldn't touch them with a 40-foot pole. They all completely screwed-up their lives.
The point is you feel this way now, but years after high school the tables will turn and with the right attitude you'll find yourself at the top of your game. This is a normal phase teens go through. Hang in there, buddy