Welcome to HCM.
It looks to be stomach infection
Take light,liquid diet
.Take care for hydration.Drink more liquids like lemon water with some sugar and salt,buttermilk,ors formula.
You have to start oral paracitamol with dicyclomin to subside stomach pain. Ondencetrone for vomiting
and antibiotic like oflox or levoflox. Lactobacillus
will be helpful.
Consult your physician for better medical management.