I Have Had Five Episodes Of Exactly The Same Symptoms

I have had five episodes of exactly the same symptoms over the last month. The symptoms last for about a day and a half and then go away for about five days and then return in the same manner. The symptoms are: stomach ache (dull and achy), nausea, head ache, diarrhea (on one occasion it was black), low grade fever and fatigue. I am simply wondering what this may be.