Draclvr, they told me she was anemic, her kidneys were failing, she was dehydrated and had a high white blood cell count and low red blood cell count. They didn't know the root cause, but they said even if they did tests and gave her blood transfusions, it would cost thousands of dollars and probably only give her a couple of extra days at most. Really, I don't know what could have happened. She was fine up until a few days ago. When we took her to the vet the first time, she didn't seem that bad, just a little lethargic, and she was sneezing. The vet gave her a shot, and she got a lot better. Then, within a couple of days, she got a lot worse leading to this result.
Thanks, Ana. I've lost other kitties before, but this is the hardest I've ever been hit before. Probably because it was just so sudden, and also, she would spend most of her time with me when I was here. Thorsgoats said he missed her greeting him at the door.