Hi. My son is nearly four, of average height and a bit on the thin side. Since Friday, he has had the flu. Multiple vomiting episodes, upset stomach after eating or drinking, no energy, sore throat. fever. Sunday afternoon he began to improve, no more throwing up and developing an appetite again. Monday and today, he hasn't gotten sick after eating but his stomach does hurt a lot. Also, yesterday and today, when he farts (which is often) it smell TERRIBLE! Is there something other than the flu that could be causing these issues?