Can't stop burping since stomach flu

A month ago, I caught the stomach flu, and shortly after, had the seasonal flu as well.  I was vomiting for three days and had a low-grade fever.  Ever since then, I am unable to eat any foods without feeling intensely, painfully bloated with gas. Besides having flatulence, I often burp for 4 hours (tasteless, air burps) after a meal, with no heartburn. The feeling of fullness reaches my esophagus and I have even dry heaved to release the painful buildup of gas. When this is happening, it is so severe that I am unable to concentrate on my school work. I am a vegetarian and I run marathons--I am otherwise very active and healthy.  I am lactose intolerant but I have not been eating dairy. Is there something that can help?