What Causes Constipation, Abdominal Cramps And Loss Of Appetite?

Hi. On Saturday i had abdominal pain and constipation. The next morning i had diarrhea and loss of appetite. In the evening i had a fever and more diarrhea. Yesterday I had really bad diarrhea and i could not eat anything. Today I am constipated again with alot of pain and bloating. I thought i had stomach flu but now i am not so sure.