She's also been almost entirely "checked out," just putting her head down and not really interacting with us, even when we call her name or pet her. She has perked up when treats were offered, and she seemed pretty interested in wet food (even though she didn't eat a lot of it), but mostly she has curled up in boxes (we have a few of appropriate size scattered around the house, as she's always been fond of lying in them) and not moved except to get water, as the kidney disease makes her always thirsty. She hasn't been making eye contact with us, just staring down all them time. And tonight she lay down in the litter box, just right there on top of her pee, and didn't want to leave when I tried to help her out. When I let her go, she walked right back into the litter box and lay down again.
So we're figuring that we'll be making the dreaded visit to the vet on Monday, when our regular vet will be in the office. If Cobweb seems worse tomorrow, we may change that plan, but right now I, personally, would like to have the support of a vet I know and trust, someone who cares about Cobweb and cares about Shannon and me, when we do this.
Shannon and I are both very stressed and upset, and we're planning to stay home tomorrow instead of going on a longish bike ride we had planned, because even if she isn't really responding to us much, neither of us wants to just head out and be gone for several hours on what will probably be our last day with her. Maybe she will crawl into my lap, again, though she hasn't done that for a couple days.
But, as I was telling Shannon a few minutes ago, I signed up for this 17 years ago when I brought her home as a kitten, and it has been way way more than worth it. She's an amazing, wonderful cat.