Animals are like your children. They are excited to see you, show you love and affection and the love we have back for them is immense.
Remember, Pinky knows she has had 16 good years with her dad..
I have a 16 year old pomeranian. Four years ago, she had liver failure.. I spent 3 months nursing her, a syringe with water to keep her hydrated and same with the food mixed in water, she wasn't meant to survive, she did.
I also had a 13 year old little boy, Sam... Black and white fluffy cat, who merrily came up the stairs and had his dinner to then, going into convulsions and being unable to use his back legs in minutes... He kissed me, when they took him away to put him down, he was in a lot of pain.. It is so hard, I understand that.
I have a diabetic dog. Husky. Kia, white with one brown and one blue eye, she's adorable around 8. They told me she would be on insulin for the rest of her life, 6am wake up to give it to her, 6pm at night, daily.. The cost as well, on the vets to get the right dosage took me 3 months and the insulin $50 a fortnight and the sleep ins? Never.. At that time, I didn't have the money, it was scary, but I just believed and worked somehow and was able to get a sale and it covered those 3 months... I am only sharing that fear you have of how.
All I can suggest is all the love you actually are already giving her.. Buy a syringe if you can and hand feed her with water slowly throughout the day so she remains hydrated, and hopefully can pee better and give her food she likes, a little chicken if you can... And, see if she can jump over it.
Sometimes just being that nurse and giving out all that love, gets them over the edge.. If not, there really is nothing or was nothing you were ever going to be able to do.
Missy, my pomeranian had a mini stroke 3 months ago, I nursed her back, after 3 weeks she can walk again just not up or down stairs.
If your cat doesn't want to live anymore, she will just throw in the towel anyway... It's her time and she's okay with that.
If she does and you nurse her, she will try to jump it enough to keep going another year or so, without all those vet bills.
I hope for you ... I know what it's like.