no songi, this isn't normal. why do you think you're fat? i mean you're so thin! there is no way that you're fat. and i think it would be absoloutly imposssible for you to EVER get fat. well, i hope you're doing good. ttyl
Personally, I don't think you have an eating disorder. You mention your height and weight so people can work out that you're already underweight for your height, and age. Very much so. And, honestly, I think you're probably aware of that.
You may feel insecure about the way you look, but that is pretty natural for your age. It's more likely that you're just feeling insecure and 'fat' because you're comparing yourself to other girls your age and feel inadequate, for whatever reason.
It might be worth talking to someone about it anyway, but it sounds like deep down you know you're not really fat, and perhaps you're just worried other people will think you are. You could maybe try to boost your confidence by buying a new outfit that suits you, changing your hairstyle or doing something to refresh your image, and help you like the way you look.
She knows that she's underweight, she says it all the time.
All of us at school know that too. I mean, I almost fit my hands around her waist. That's a little too skinny. I want to help her, cause I really like her a lot, but I don't know what to do.