Well, I may finally be on the mend. I'm now on my third round of antibiotics for this nasty bronchial infection. I'm still congested and coughing, but not as much as before. I've taken a week of the drugs so far and have 2 weeks' worth left if I need that much.
I returned to the gym on Monday after two weeks away (give or take) and took it easy but had no trouble. I took a walk today at a brisk pace (for me anyway) and did pretty well. My resting heart rate is lower too, which makes me think I'm getting better oxygenated.
I saw my infectious disease doctor last week, who theorizes that my health problems and immune difficulties started long ago with an enterovirus (my doctor is author of reference #5). He recommended I start taking Oxymatrine, an alkaloid extract from the Sophora Flavescens root, long regarded as a healing herb in China. I've only taken about a week worth so I think it's too early to say anything decisive.
All I can do is hope, trust and pray that someone will come up with something that makes a difference.