Aw Gus, I'm really sorry.
Been through this myself, too many times. Sigh.
The little blighters don't live as long as we do (in human, not
cat years), that's the problem. Gone too soon! Always, always ...
But, ya know, you can always make another critter very, very contended & loved. And you can bring new joy into your own life, too, by adopting that (preferably needing a home) new critter. This has been my time-honored way of coping with such sad losses. I commend it to you, possum.