Hi, I Am A 38 Years Old Woman. I Have

Hi, I am a 38 years old woman. I have been fighting with a cough and sinus stuff for about 2 months. I did go to the doctor and they gave me a steroid for sinus drainage and green mucus. I have not got better, actually feel worse these last few days. My cough is still bad, it worsens with heat and bed time. I cough up slimy green stuff and my cough sounds crackly. Today for some reason I feel like my body is shutting down and tired. About 7 years ago I stopped smoking and now my worry is lung cancer. What do you think?