What Causes Vomiting And Diarrhea In A Baby?

My son is 13 months and on Sunday he had a few loose stools then vomited after breastfeeding. All day Monday he had diarrhea until I left fir work then no problems for dad. I work nights as a RN. The following day diarrhea began again and ceased in the evening. Today he has vomited after breastfeeding as well as diarrhea. I am wondering if it is the breastmilk. He is afebrile and no other symptoms.