However, I did "call in" today. I was scheduled to play today's understudy rehearsal, but since I'm sure that spending five hours in the frigid air-conditioning* of the theatre yesterday didn't really help me at all, I asked George, my conductor, if he could cover the rehearsal. He was more than happy to let me stay at home and rest and recuperate before tonight's show.
I actually have some minor fixes to take care of in my keyboard part, so I can take care of that today too. -Which is a good thing, since my "sub" goes on this weekend, while I audit the conducting chair.