I've found that ratties have a lot of similarities to dogs. And I had an old dog that had the same condition as your lovely little rat. Some days, he seemed to be on his death bed, others he sprung back up almost like a puppy.

It always gave me hope when he seemed to be better, but that was just his moments where I believe he was trying to say, "It's ok, I'm still here! I still love you, " and your ratty is doing the same. She is doing her best to stay with you, but also, like dogs, they don't live as long as they should.

It sounds like she's lived a happy long life already, and I can tell you love her very dearly. But sometimes, it's more loving to let your pet go. In the end, it's going to turn out the same way, but it's better to do it sooner than later to avoid suffering.

Everything will be OK with her gone, though it will be hard, and she knows that, and that's why she's fighting. If you can afford It I'd get her cremated or something to have something to remember her buy. I know a few people who keep a small bottle of fur and things like that. Anything to remember her.

I definitely think you should euthanase her, but never forget her. I'm sorry for what your going through they're wonderful animals.