3-month old sick? Advice?

He has a stomach bug. When they throw up curdled milk and sleep a lot, especially with diarrhea, it is a virus. Nothing to do but hold him, love on him, and rub his tummy. He doesn't sound dehydrated, and with no fever, should be fine. You are lucky to have such a good tempered baby, especially when they are sick. Good job Mom (or Dad)! You do everything to make him understand it is okay, and Mommy will be here especially when you feel icky.