What Causes Vomiting And Diarrhoea Along With Low Fever And Chills?

My entire family has had dihrraia and vomiting. It has lasted three days. We have had a low fever, chills and cramping. We have no appetite but we are drinking water and G2. My sixteen year old is feeling a lot better today but my husband and I are still not feeling like ourselves.
Is this just the flu?