Just an update, and FYI, the 411, for those who have been following along at home:
I went back to the doc on Saturday. I did indeed have a lingering infection in my lungs. The z-pack, while convenient and usually effective, wasn't strong enough to knock the infection out of my lungs.
So I'm on another antibiotic and something for the asthma-like wheezing that happens when I cough and that almost sent me to the hospital early into the illness.
And I'm feeling much better already.
I love my doc. I don't mind seeing the PA or NP in a pinch, but no one knows me like my Doc!