My 4 year, is 38 , 41lbs is in preschool, came home 5 days ago with diarrhea and vomiting for 24 hours. Seemed fine for 2 days and now has loss of app, diarrhea again and has vomited once. No fever and drinking fluids, tonsils seem swollen but no infection showing. How long do stomach bugs last? Is this normal?