I'm 13, about 120 pounds, and 5'2. I'm never really hungry and when I do eat, I usually get full pretty fast, or start getting a stomachache/ headache. I don't eat breakfast, I eat lunch sometimes, and I always eat dinner. I'm also always feeling tired, even after I sleep for over 8 hours and I'm always thirsty too, even after I drink a lot. I'm just a little worried and want to make sure there's nothing serious.