Hi Madam/sir, I am sorry your son is suffering from diarrhea. Don t worry, usually diarrhea are caused by viral infections. They usually last for two to three days and settle down on their own. Infections can cause spasmodic contractions of intestinal wall resulting in abdominal pain. But they also subside along with diarrhea and is not a cause for concern. Just see if there is blood in stools along with pain while passing stools when antibiotics may be needed. since your child is active and vomited only once, he can be managed adequately at home by giving him plenty of fluids as water, butter milk with salt, tender coconut water, rice kanji to replenish what he looses through loose stools. ORS packets(electral) can be dissolved in water and 100ml per loose stool can be given. Diarrhea is a mechanism of removing all unwanted organisms out. Once they get out, your child will become alright. Take care, Dr Balaji C