It started a couple days ago, I'll eat a big meal and I'll be REALLY hungry 2 or 3 hours later. Like I never ate. I'm 17 years old and i'm in show choir so i'm kinda active. My mom bought me some multivitamins a couple days ago would that have anything to do with it? Otherwise why would I get hungry so fast? Its kind of irritating and I don't want to keep feeding myself all the time because I don't want to gain lots of weight. What's happening?