What's wrong with me?

I'm only 15 years old and for the past couple days, I've barely had an appetite, I'm nauseous, I feel full, I belch with the taste seeming like there's nothing in my stomach, and I have gas. I've been taking Protonix (pantoprozole) for a couple months, and even went in for an endoscopy. The endoscopy came back clear, but I still have these problems. I was thinking that maybe its not that my stomach has too much acid, maybe it has not ENOUGH acid. Help! What should I do? I'm just about to fast for a couple weeks until I see my pediatrician.