I Have Had A Cough For Several Months. Low Grade

I have had a cough for several months. low grade fever. been diagnosed with bronchitis by most recent Dr. then my recent blood work shows high white blood cell count and low hemoglobin. I have seen three different Drs. I am weaker than usual, usually live a very active life tennis , golf , walking etc I have been prescribed twice Zpacks. still no results. Male age 71