After a little waffling, I went to the gym this morning, and ended up feeling much better!
I started on the recumbent bike to warm up, but by the time I was ready to try running some on the treadmill, all five treadmills were full. I went 40 minutes (7.29 miles) on the bike without someone getting off the treadmills. I got on the elliptical machine for 10 minutes (.84 miles), which was a change of pace. A treadmill finally freed up, so I hopped on for 5 minutes (.40 miles), so I could record that I'd run some today! The whole workout felt surprisingly good, and I'm thankful for that, since I haven't worked out since a short stint Wednesday morning. I was afraid of beginning to lose some fitness.
My mileage for the week and the month will be a little puny, I'm afraid, but these things happen.