My son is 4 years old. He has had stomach pain above his belly button for almost 2 days now, but we thought it may be a stomach virus. He threw up a few times day before yesterday, then had a little bit of diarrhea. He acted like he was feeling a little better yesterday, had a few bites to eat, but then threw up during the middle of the night. Today he has tried to drink and eat a few bites, but his stomach is still hurting above his belly button. What could be wrong?