Male, 26, sick for the last three days. At first symptoms were limited to fever (about 40 degrees), chills, loss of appetite and nausea . Now, fever is down to 38.5, but nausea/appetite issues persist, chronic diarrhea , and muscle pain, especially in the middle back, sternal area, and jaw... any ideas about the cause? I ve been to a hospital to rule out the flu, but at the time didn t think it necessary to get a diagnosis.