Thanks for your query.
Your child had symptoms of gastroenteritis
which takes few days to settle
pain abdomen and loose stools persist for some days.
I suggest you to give probiotic
like lactobaccilus sachet for 2 to 3 days.
Give plenty of fluids,lemonade,curd,rice porridge.
His activity and appetite will resume in couple of days.
Wishing your child good health.