So I was getting my laundry from the laundromat last night, loading it from the dryer into my bag on the floor. Well, when I went to stand up, I couldn't. My back was all seized up. A lifetime of memories from the countless sitcoms where the man hurting his back has been the central theme flashed through my brain. After all the reruns finished, I was able to straighten up. I managed to stagger the block home carrying my laundry---remember, in the first part of the show, the man always tries to tough it out---and collapse into bed. I dealt with it the best way I knew how, by moaning for a while and then going to sleep. At some point in the middle of the night, I got out the hot water bottle. That seemed to help. But when I woke up this morning, it was still pretty bad.
I'm staying home and horizontal today. I think it's just a tweaked muscle, since all the pain was in my lower back, and there was no numbness or anything, but I guess I will finally be going to the doctor too (which is how the sitcom usually ends).