My daughter is almost three years old. This morning she had diarrhea i…

My daughter is almost three years old. This morning she had diarrhea immediately after waking up. The stool was watery. And then she got sick to her stomach, but couldn't throw anything up from her mouth because she was hungry. What should I give her? I think it might be a bowel infection, of course, I will wait and see, but what should I do if it happens again?