Had the same thing happen to me, Bongo - literally too. I mean my cat was about 17 when she finally went. Worst part was, I had just laid down for bed and was about to fall asleep when my buddy who was over (and decided to stay awake playing Playstation) knocked at my door and just said she was gone.
Still, don't be too upset. 17 years for any housepet is an amazing thing. Just be glad that she was around when you needed her to be.
Trying to dig a hole in frozen ground sucks.