I don't know what your relationship is with her but if I saw you at 75-80 lbs at the height of 5'4", it would have scared the heck out of me, and I'm not your sister but a stranger. I can only imagine she must be relieved to see that you've gained weight and feels a certain happiness towards your being "fat"-it's a pleasure and a relief for her, I'm sure.
Know that she says that with love and it's her way of saying "I'm soooo very happy that you're better, I was really scared when you were really too skinny and boney."
(((((((((((jessica)))))))))))))