Ugh. That little sore throat from last week, yeah, it got bigger. As I sat with hands folded on the narrow airplane seat I was acutely aware of the coughing and sneezing from around me, I'm flying during cold and flu season.
Travel opens people up to getting sick. You are touching things that others touched, being exposed to a variety of other germs that might not be native to places like Iowa, and there is the mental stress of travel, which seems to wear down on the body regardless of the germs one encounters.
Work travel is not vacation. It's great to travel and see so much of the world, a huge perk of a job, in my opinion, but ultimately there is a job to be done, meetings to be had, problems to be solved, people to placate, and it all must be done before the return flight. While sometimes there is a day, or at least half a day of opportunity to see something a little touristy, by that point most people are so tired that we just want to get home and sleep in our own bed.
Sick on a work trip? Too bad for you, but it happens, the show must go on, and remember eventually you will get home to eat some soup and drink decaf green tea.