15yr old has stomache pain vomitting and headaxhe for 4 days had yellow diarrhea on 4 day, hes taken pepto bismol, (bismuth subsalicylate) liperomide and gravol what's wrong?

Viral illness: Most likely a viral illness. Treatment should include clear liquids (with electrolytes!), tylenol (acetaminophen) for fever. If diarrhea is bloody or foul smelling and fever is 103 or more, see your doctor. Viral gastro should last 3-5 days. Resting the bowel with clear liquids is most important. Pepto and the other meds are not usually necessary and have some risks.