Thank you, everyone, for your kind comments the past couple of days. Sorry not to respond to everyone directly. I heard from the vet, and it sounds like Tori is better. After a night in the hospital and a blood transfusion, she's stable, and the vet says she’s looking better, though not quite there yet - her red blood cell count is about half what it should be. They’re going to do a battery of tests to find out what’s causing the anemia. The good news is that most things it could be are treatable, so I will be hoping it is one of those things (and not cancer or feline leukemia or other scary things like that).
If all goes well, they expect to release her this evening, although they may need her to come back for follow-up, further testing, etc. But I'm sure she'll be happier at home.