I'm so very sorry for your loss of your cat. If you ever get another cat and want it outdoors for even part time. Have you thought of making a a safe outdoor enclosure for your cat. Your cat would be safe from a lot of stuff. Please try to move forward and don't think about the past just let it happen. My sister lost her Bengal cat to kidney renal failure at age 7. All cats will kidney renal disease that's what got my 18 year old Bengal cat. Doing something for the local Humane Society was very helpful to them and me.