I kinda feel left out... body issues... =(?

Okay wel i'm 16,and i'm pretty popular in school like people compliment and tell me your pretty, u' v got good legs and all well there's this thing like that sometimes gals who hate me make fun of me by saying that you're too skinny,which is true,its not like I'm dieting or anything like that i eat a lot but i don't know why i don't gain weight like I'm only 36 kgs and 5'4 in height,and this gal who likes my bf told him that she's all just the face,i can give you what you want,its not that my bf is interested or anything but it feels weird that maybe his friends tease him that you're gf' s too skinny,like i don't know what to do its like i don't have fat at the right places,previously it never bothered me but now it does... like all i'v got is bones,someone tell me what to do?? How do i get a good body ? =O