My 16 year old son has had a low grade fever, no higher than 99.6 F off and on for the past 8 days. He also has a very gassy stomach, a lot of burping but no nausea or vomiting, no stomach ache. He also has some fatigue and little appetite when he has alot of gas and running a fever. When the gas isn't very bad, then he is able to eat normally. Twice he thought it was going away for a day or two and felt better, then it came back again. A couple of times he said he had some liquid gas and only maybe a touch of diarrhea. He has no other health conditions. Could this just be a virus or maybe strep?