The airline was nice and only charged me $350 (a change fee plus fare difference) to come home a day later and avoid infecting an entire cabin with whatever I was carrying. I had thought they might be a little forgiving with the change fees, but I overestimated them. You would think the airlines would be happy to facilitate a change to keep sick people off their plane -- I would have been happy to go to an urgent care clinic to get a doctor's note verifying that I was ill.
But, anyway, I'll be back tomorrow. And hopefully healthy, too.