I know the sweet anquish of losing a pet that has loved you loyally longer than any other wife/husband. Creatures. They are dependent on us, and we reward them with care and affection. I had a black Persian that lived to be 18, got hit by a car, but she was well cared for and brushed weekly. I mourned for her for 3 months. One night after her passing, I swore she jumped up on my bed. When I awoke and sat up I saw her sitting in the darkened hallway. Then I was able to "let her go".
She had come to say goodbye.

I now have an aging male Siamese persian named Zeta who's about 17 and losing weight and getting weaker. He's allowed a special spot on the couch with a cover just for him, and he gets fed first with the best of catfood. I try and appreciate what's left of our companionship.

So, I know your sorrow and honor it.