Confused..

Maggie
So.. I had my appendix out not long ago.. I've always had an issue with no appetite, weight loss, nausea.. All that stuff. So I found out I need to get my gallbladder out... I've just been feeling so nauseated.. I had a flu bug a week ago.. But I wake up and have a little protein drink that has like maybe 7-10 g. Of protein so not much, then I usually have some string cheese or something little in the afternoon and kind of just pick at dinner.. Sometimes I eat a decent amount of dinner well usually. I just am wondering if I'm not eating enough for my weight? I weigh like 110 or so and I'm 18, I just lay down at night and get a feeling that I'm hungry but I also feel like I'm gonna get sick.. Any idea what this could be? Or is it just my gallbladder? I just hate feeling like this at night especially cause it keeps me up! 
(I'm getting my gallbladder out on Tuesday)