Sick baby with lots of diarrhea

Bailee

Okay so my 13 month old has been sick since last Thursday, we got told he had a sinus infection so got antibiotics to take for 4 days and cough medicine every 6 hours as needed. Well yesterday he hasent approved and so took him back to the doctor and was told he has a croup cough and was given steroids to take for 3 days, now after coming home from the doctor he diarrhea 6 times yesterday and have diarrhea almost 3 times in a hour and a half, what should we do? He drank a whole water bottle full of Pedialight yesterday in under a hour! So should we give the doctor a call again? First time mom here