What Causes Persistent Pain In Abdomen Along With Loose Stools?

My belly has been hurting so bad and rumbleing n exploding it seems. my daughter woke up Monday throwing up and diarrhea then my 7month old woke up the same I was feeling fine but then monday night comes n my belly felt weird I think its the flu but then i think it was from the food that we ate out from since sunday everything hasnt been good for us ive been having black watery poop and ive been burping up the taste of rothen egg pleass help me