Hopefully since this was posted on april 14th, it's sorted by now or you have gotten medical help if it persisted.
This can happen if you are exposed to the sun to long, heat stroke can make you feel chilled with a fever and a upset stomach.
Or really it could just be a virus. Stomach flu, a bug etc... If you do throw up and or have diarrhea then it sounds like a stomach flu. If you really don't feel sick then I would try cold pills or something for your fever and ''Pepto Bismol'' chewables for your stomach. That helps: nausea, heartburn, indigestion, upset stomach and diarrhea. Hope this helped