Annie, I'm so sorry. We've been there too many times and it's always so hard. You definitely did the right thing for Cinders.
I grew up with a Cinder cat too. She lived to be 20 and was an outdoor cat her whole life because my parents didn't believe in having animals in the house. They grew up on farms. Fortunately for Cinders it was when their home was somewhat remote. Now it's the middle of a large city.
I hope you can soon get back out to your happy place and let your garden cheer you up. From the looks of your garden contest photos, you have a lot of wonderful flowers!