Do you think im anorexic?

im 13 and 5'5 im underweight and i know i am. i think im thin because as i child i was very active track, cross country, rugby, v-ball and i eat candy alot i use to eat a bag a chips a day ( those convienience store bags), i eat macdonalds from time to time i bloat alot so i think i like kinda big after i eat. im 5'5 . i look at food labels because i wanna know if its good for my body and like im an over achiever im almost 100 pounds. sometimes i am afraid to be fat. but yeah, i dont think am anorexic..