That is so sad to hear about Chance, and I deeply feel for you. Just remember to look at your own loved cats for comfort, and they'll make you see you tried the best you could for him, and that in his last days he was loved by somebody and cared for. He is now at rainbow bridge dancing away with all the other pet talk cats, and they're telling him stories about how great it is to have a home and that he will have one with you again one day