Sorry for your loss. Prayers sent for family and friends as they figure out how to cope with the loss..
To answer your question, yes, I can somewhat relate to what you're feeling, although my loss wasn't quite so sudden. My childhood best friend died from breast cancer earlier this year at age 42, around the same time as I had my own cancer scare. She was a gentle, loving person with a great sense of humor, and I have often wondered how I can be so lucky when she was not. She had 6 children (the youngest was 4, same age as my youngest) and was a very devout Catholic. If you're a believer of such things, maybe that was why she was called home, because she was ready.
I know she would never have been "ready" to leave her family, but spiritually, she was in a good spot. Probably not too helpful for you, sorry...
It does get easier with time; eventually you stop questioning the why, accept it, and try to make yourself into a better person/spouse/parent in honor of the lost one.