Baby with fever, diarrhea, rash

My son is 9 months old. Friday and Saturday he had a low grade fever, he was fine on Sunday, this morning he woke up having diarrhea, and now he’s developed a rash on his face/neck, back and chest/stomach. He no longer has diarrhea or a fever but I think all those symptoms, one right after another is a little odd. I noticed the rash after his drs office was closed, they don’t look like hives, they’re not raised or seem to be bothering him. But if he has the rash in the morning I’ll be keeping him home and calling the dr. Does anyone know if the symptoms could be related or why? He hasn’t had anything new to eat, no new soaps or detergents, nothing different whatsoever.