I'm really sorry for your loss.
To be honest, I can't quite understand how that must feel. I own a cat since I've been a little child, and he's still alive today - he's 20 while I'm 22, so I really don't know a life without him, but if he dies, I'll probably be also as devastated as you are.
He sadly got blind two years ago, and is now very, very slow, passive and sleepy, but still generally more or less healthy, at least the vet said that she saw younger cats that looked a lot worse.
I also found out that even animals can turn white, I never realized that before. He was almost completely black when he was younger, but when he got older, he grew more and more white hair, and now even his whiskers turned completely white, which interestingly gives him a rather dignified look.
On another note, my grandparents owned a dog, some mixed race wire-haired dachshund thing, that was really awesome. She loved apples for some reason. If you would throw one she would run after it, which always looked hilarious in higher grass, because she had to hop through it like a rabbit. And she also loved wrestling for the apples, and you could pick her up by the apple when she had one in her mouth, and she just wouldn't let go.
I also remember one time when my cousin lined up some apples on the road in front of her, and the poor thing didn't know what to do, she just couldn't decide.
Sadly, she died a few years ago (though she outlived her owners), but that was the most awesome dog I've known - normally I'm more of a cat person, but she was definitely like no other dog.