Wanted to respond to you here so I don't derail the thread...
"And that's why they suffer severe consequences."
What consequences? Somebody said that retaliating just brings you down to their level, and that's pretty true. I used to get picked on all the time, but now I just let it roll off my back. Then again, I'm a lot older and that's made a lot of difference. You're young and just need to grow thicker skin and take your life into your own hands.
You mentioned something about being overweight, and if it bothers you that much, do something about it. Go for walks, join a gym, buy some free weights, or anything like that will help. I'm sure getting in shape will help your self-esteem a lot. (Not to mention the social/sexual benefits, too. Haha.)