My cat died last night in my arms, and I feel bad for not euthanizing her.?

It sounds like you handled a very difficult situation with love, compion and dedication. I am so very sorry for your loss. You did not do the wrong thing. An animal does not need to be euthanized if it's not in pain, and it sounds like she had a very peaceful ping - at home, in familiar surroundings, in the loving arms of her family. Please do not feel guilty for that. You positively gave her the best and most peaceful death any animal could wish for. My prayers are with your family for comfort right now as you grieve Koshka.