I'm 16 and about 5' 4" and I used to weigh somewhere around 115 and 120 lbs. I recently became a vegetarian (for animal rights reasons, not health but the weight loss is an added bonus) and lost around 10 lbs, so now I weigh somewhere around 105.

Sometimes I feel really happy about my new body and I like it, but then other times I'm just still so unhappy. I feel like I could lose 20 more lbs and it would never be enough. I always want to feel skinnier.
And also because other thing will always bother me that I CAN'T change. I'll always be flat chested (which pisses me off) and I'll never look like my sister (which is frustrating for me - she's gorgeous)

I feel healthy and glad that i lost the weight but now I'm sooo nervous about gaining it back. I get really frustrated with myself when I eat a lot and have even (in moments of built-up guilt/frustration) tried purging (it hasn't worked so far). Every time I look in the mirror I check every inch of me to make sure I don't look like I've gained any weight ANYWHERE. And whenever I eat a lot, it's like I can FEEL myself gaining weight. It's become an obsession.

I know I'm spewing a lot of problems here but I guess I just feel like i have schizophrenia when it comes to my body. Sometimes I love it. Sometimes I hate it SO MUCH. I wish I could just be happy with how I am now, and stop worrying about it.

I don't wanna say you're underweight, but being 5'4 and 105lbs you might look a bit too skinny, but i've never seen a picture.. I honestly think you probably have nothing at all to worry about, 115lbs is skinny, but I know no matter what people tell you, you won't believe them. I'm sorry if any of this sounds rude, but even if you gained 10lbs you'd still be skinny.

I have the same problem though, people say i'm skinny and stuff and I honestly don't think I am, I hate my stomach and stuff :|

I would really consider getting a whole new wardrobe and find clothes that fit your body, that might be some of the problem.

it doesn't sound rude at all.
I think that's my issue - I'm always suspicious of what people tell me. I always think they are just being nice if they say I look good.

I really notice that I have the most problems with my appearance when my sister's around. I know it's not her fault she's prettier than me and it's not like she rubs it in my face, but I'm ALWAYS comparing myself to her and I never measure up. No matter how nice I look, if she's around, she'll always look better.

yeah most of my pants are too big and it makes me feel fatter. -_-' lol
but I'm so sensitive when I shop. if one pair of pants in my size doesn't fit me I worry I've gained weight, even if deep down i know that's completely illogical! I'm crazy!

p.s.
I hate my stomach too! I always get grossed out when it expands after I eat.

gah I'm so whiny, I'm sorry.

Everyone wants something that they can't have. It's human nature. What you should be concerned about is what is healthy for you. I've been torturing myself since I was little about being skinny. And now, I'm happy at where I'm at, I'm 5'8" and weigh 150, I still wish I was 120lbs or less. You should look up to your sister, not put her looks on a pedestal, besides women look best in their thirties. Just look at some celebs. Good luck with everything!