Cold, Fever And Cough. Strep Test Positive. Taking Z-pack. Have Congestion In The Lungs. Any Advice?

HI, i'm 33, female, non smoker non drinker. i've been sick for around 6 wks now. Initially i thought i had a bad cold, but most likely was the flu as i was runnig high fevers and completely in bed for 4 days straight. for the remainder of the week, i developed a terrible wet cough and felt incredibly lethargic. the following week i visited my nurse in teh office, and a strep test proved positive. she put me on amoxicillin for 10 days. i had both my children and husband checked to make sure, all are negative for strep. 10 days later, no more sore throat, but i'm stil incredibly tired, and 3 days later came down with a fever again and cough started getting worse again. fever lasted around 2 days, then broke and i seemed to be getting better, but sure enough 5 days later i was sick again with the nasty cough still there as well as fevers, bodyache, runny nose etc. i went back to the doctors, and he said there was a little congestion in my lungs. he prescribed me a z-pack. i'm on day 3 today, feeling very nauseous form the meds, but overall no improvement. stilll coughing, still having body aches, still having a runny nose. help pls!