i just dont understand. last year i was about 5'1 and 75-80 pounds. i was on the verge of being hospitilized. now i am around 5'4 and around 100-105 pounds. so , im still underweight. however, my sister calls me fatty. she sees it as a joke but it still kills me inside. i know shes just kidding because she knows im underweight but she keeps calling me fat. should i talk to her about it? tell her its not that funny.

help? =/