What Causes Severe Cough With Yellow Sputum And Sinus Congestion?

I ve had a cough for the past four weeks. I ve had congestion in my chest over that period of time. It seems somewhat better than it was. Worse at night, it will wake me up with severe coughing fits. My doctor has put me on Keflex(?) for about 4 days and then a week later Cednefir(?) for about 4 days. I m now taking prednesone and a cough medicine with codeine. I m exhausted all the time, and I am now coughing up yellow sputum along with sinus congestion. I am also experiencing frequent cold sweats as well. A recent blood test showed that my red blood cells are smaller than they should be. My blood pressure is good 120/80, and my resting heartbeat is about 84. I have diabetes, taking metformin, Invokana, glipizide, and Victoza. Anything you would suggest?