The PDX pride mommy here with an update. Tabby is still hanging in there, but today she has been "spacing out" most of the time. It took her a few minutes to even realize that my husband had come into the bathroom and was talking to her, then she slowly came out of it enough to start yelling at him for attention. After a few minutes, she went and lay down in the bathtub, uncharacteristic behavior for her, and has stayed there. It will be sometime this coming week.
Some of you have wondered if it is hyper-T. We have had her thyroid levels tested over the years, and that isn't the reason, but thank you for offering helpful suggestions. We appreciate all the concern and have been repeatedly telling Tabby that everyone loves her and we're all here for her.