Okay, ya know, emo, I feel for you, I really do. Your brain is telling you you're too fat, even though in reality, you're not... in reality, you're killing yourself via eating disorder.
So I'm sorry, but I gotta say something I ordinarily wouldn't, because it's a little mean... but maybe that's the only way to get through.
SIZE ZERO IS A WOMEN'S SIZE. Men do not wear "size zero." A women's size zero has a 23-inch waist, if we're talking pants, and in case you're not aware, the smallest size men's pants go to is a 28 (inches). There's a reason for that. Guys aren't tiny. Those who are, usually have a big problem with it, and bodybuild to try to bulk up. Men are NOT obsessed with how skinny they are... if anything, most men want to be bigger!
I'm not saying you're not ftm, not a dude, or what have you. But for god's sakes... if only for the fact that you're being a little frickin' girl about your weight, quit it! Get some help! I've been sympathetic before, as have the rest of the guys, but god... just get some help. You're not too skinny, you're not going to be beautiful if you lose 20 lbs... you're going to be dead. And what's the point of that?
SD