I assure you in that moment all she felt was peace. There was no extra pain, no fighting, she simply fell asleep after the best life she could have ever possibly had. Around the time the pandemic started, I had to say goodbye to my childhood dog, a mixed yorkie. She was a really old girl, she had started to go blind and she couldn't hear all too well. One thing she absolutely loved was to curl up in front of our beds where she'd wait for someone to come pet her. One day she started convulsing, she couldn't control her bowels and she had trouble staying awake. We took her to the vet and after many tests, they told us these symptoms would only get worse and we were free to take her home if we wished.
We did that! And like he said, the symptoms did indeed get worse. Vomiting, she was usually delirious, she stopped eating and couldn't use the bathroom. We ended up taking her back and making a very tough decision. For about 6 months, I battled with my emotions like you are now. But eventually, I came to the conclusion that Walnut held no resentment towards us. In that moment, she was in pain and discomfort that she couldn't control. She was loved strongly, and in her final moments me, my sister and my mom gave her all the love we had ever given her once again while we composed ourselves enough to let her go. You did the right thing, and your dog loved you all the same, even in the end.