Aww alam ko na stress yan, lalo na first time! Hydration lang talaga ang most important, ORS (oral rehydration solution) or kahit banana, rice, at crackers muna ang foods, at maraming tubig para hindi siya madehydrate. One of my mum friends swears na kapag may diarrhea ang kids niya, she gives them coconut water din kasi natural electrolytes siya at sure pang-lasa para sa kids! But honestly, if it's been more than a few days o nakikita mo siyang very weak, better have a pedia check lang para sure, sometimes may underlying cause na kailangan tingnan talaga ng doctor.