A month ago, I had what i believed was the flu (fever, chills, sore throat, runny nose, cough with phlegm etc) and after some days, I believe I had a sinus infection since my head was hurting pretty badly and felt like a ton of bricks, while still having a bad cough with phlegm. My doctor put me on a zpack. Well, a month later, I am still running a low grade fever. I will have a lowgrade fever about every afternoon. It will usually reach to 100 but never over it.I have yet another cold, right now, with sneezing, headache and runny nose. What could be going on? what can i do? why wont this low grade fever go away? my head is always hurting.