What will my son's dr do for upset stomach? Luca threw up this morning and has had about 5 poopy…

What will my son's dr do for upset stomach? Luca threw up this morning and has had about 5 poopy diapers in the past 3 hours. He screams and cries in pain which is breaking my heart :( I want to take him to the dr but I don't know if they'll be able to do anything. Anyone else go through this? Luca is 9.5 months old btw.