Please. My 17 month old is sick he has vomiting,slight diarrhea. He’s not fussy but if he eats anything he vomits I gave him

Crackers and he threw up I tried Gatorade but he refuses he only wants milk maybe some water but he wants milk. Is it ok to give milk how long can he go like this . I really don’t want to take him to the er with the flu going around

He seems nauseous as well bc he gags a lot

Could this a stomach bug