Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Acute onset symptoms you mentioned are suggestive of gastroenteritis most commonly. Do revisit your pediatrician to review the case and plan treatment. continue oral rehydration therapy. Most importantly source of infection. Usually occurs through unclean water, food or not washing hand before food. So ensure good hygiene practices so that it will prevent the infection to others or in future to child. Hope I have answered your query. Let me know if I can assist you further.