Feeling Thin

I’m thin…now before you click out of this question..hear me out….my the other women in my family are always making comments about my weight because im the thinnest one…every time they say something doesnt fit or is too small..I get..”the glare”..I know they’re just kiding most of the time but im kinda getting sick oft the comments about my weight from every one…it doesnt help that im getting accusations from the people at school about eating disorders..but now my mother is constantly interogating me about my eating habits and she even told me I looked sick and that she was going to take me to the doctor if I didnt start gaining weight..I cant help any of this..I eat twice(no exagerating) waht most people eat and I mean, I exercise a bit but not excessively…I dont know why im so…thin…its never bothered me before but the comments and accusations are getting frustrating….I dont know whether I should (or how I should) keep trying to gain weight since it hasnt been working very well…or how im supposed to handle all the remarks..any advice would be really helpful on this topic…