God, I remember when I had to have my cat put down...so long ago now. She was already old, and suffering from kidney problems, as old cats do, but a dog chased her, and her tendon snapped. Had to have her put down. I couldn't go to the vet to watch.
Sorry to hear about your cat, Dotsie.
"What have you been doing since you stole that antique TARDIS of yours, since you first landed on Skaro? Shouting 'Look at me!!! I'm not fighting a war!', while you battle the Daleks all the way through space and time."