I'm sorry to hear what happened. Freaky stuff just does sometimes with no real way of preventing it.
We had to keep our chocolate lab fenced in a very small yard, but he had come from the country so he was used to running around. One night we were going out to eat and we thought we would just let him run and explore cause we felt guilty for keeping him confined. When we got home, we found he had been hit by a car and died. That was one of the best dogs on the planet and I still miss him. I won't ever forget the time we had together and how he loved us. Talk about feeling guilty. I pray that your heart heals and that you'll be able to look back without pain, just good memories for the time you had together.
I am feeling guilt right now because the poor thing died all alone at the vet. She died sometime between 12:30 a.m. and 6:30 a.m. this morning. Now I wish she could have been at home at my son's when she passed. But he had said he could not deal with her dying at home. All the time I thought her name was Patty, like the woman's name, but it was Padi, sounds the same. Don't know whether other cats grieve a cat that all of a sudden is no longer there but I guess he will see. I've really had a hard time today.