It's been an estimate of two monthes or so since I've had the following symtoms. Please give me guidance as to this issue ):

[Momotaros]

I am fifteen years old, atheletic, and 5 feet with the weight of approxiamately 115 pounds. Whenever I've finished eating (this applies to small&big meals) I have to burp excessively. At certain times, I reach the point where I have to retch up my food or either feel constant nausea in the midpoint of my abdomen. In addition to that, during those symptoms, my stomach (occasionally) feels resolutely empty. I was not concerned about this when it first began to occur, but because it's been prolonged I am searching everywhere on the internet as to why my body is functioning so improperly. I've read articles from gallbladder malfunctions to even cancer! At this point I am perplexed and confused.
Please give me some advice to this matter.

[Momotaros]

Thank you very much :)