I agree with your Internist. Before I responded to your question yesterday, I was thinking along the same lines. It seems that once you acquire some type of infection that needs medical treatment (antibiotic), you immune system is impacted enough that you are vulnerable to other infections.
And, technically, though your body temperature is slightly elevated, it is not considered significant (medically speaking) until it goes over 100.4 degrees. You body temp can fluctuate a degree either way normally throughout the day.
If you have acquired a mononucleosis type of virus, which could either an Epstein-Barr virus (EBV) or cytomegalovirus (CMV). These types of viral infections typically linger on for weeks, sometimes months. This is why people may "relapse" if they over extend themselves. Its because the virus is still present, and when you over burden your immune system (stress, poor eating habits, lack of rest, etc) the symptoms reappear. Eventually your body will win out and overcome the virus.
When you had the "viral bronchitis" it could have been the acute phase of either of these viruses.
Help you body heal itself by getting plenty of rest, eating a nutritious diet (cut out junk food and soda pop for awhile), getting plenty of fluids and try to not get stressed out about anything. In other words, Baby yourself.
Here is some more information about the Mono Virus from MayoClinic.com