What Causes Persistent Cough,shortness Of Breath And Fatigue?

I have had a presistant cough since the first week of April , my doc gave me 250mg azithromycin (5-day) and suggested I take sudafed, it s now been three days on meds and the mucus is still coming out and the cough has gotten stronger today, shortness of breath, and extreme fatigue , haven t been able to sleep, loss of appetite and not sure if my balence is off because of lack of sleep or my ehlers-danlos , or because of being sick , but I just don t feel right, it doesn t feel like a normal cold or flu and my doctor thinks it mono but said I would start feeling better by day 3 of treatments , but today is day three and the cough has gotten worst... What could this be ? Also been itchy since taking the meds and have had a pain in my back for a month now two that is along the spine between the shoulder blades maybe a little lower