Hi, my 2 years old son was vomiting 6 days ago, and stopped the next day. So we think he had a stomach flu. Since then, he has no appetite, and sleeps a lot. Today he had a loose, yellow stool. We brought him to visit the doctor three days ago, and at that time, nothing else seems wrong. Is this still consider stomach flu that it takes time to cure. Or we should check him out again?