Thank you again for your kind words. Sadly, I knew that if I didn't pursue the more tests/treatments option that it would be time to say goodbye but yes I didn't expect it to be the following morning. But it wasn't fair to keep him alive while he was having more and more problems breathing. He had been losing weight, was coughing more and more, and most importantly was struggling to breathe much of the time and was uncomfortable, shifting position very slowly to accommodate the fact that his breathing was so difficult. He was tired of fighting to breathe and was also worn out from repeated vet visits and the various treatments over the last couple of months. He was having more bad days than good days. And I wanted to say goodbye while he still had some nice moments in his day rather than wait for him to waste away until he had no quality of life at all. And I didn't want his last moments to be undergoing an invasive procedure while I wasn't there.
On the morning that we took him in for the euthanasia his breathing was up to 80 and he was not really interacting and seemed very bewildered and uncomfortable and would only eat if food was held right in front of him. I think the only other option would have been back into the oxygen chamber again.
But it was a very tough decision to make and I will miss him very much. Part of me worries that I did it too soon but I have read that a week too soon is better than a moment too late and I am trying to remember that. What you say about our animals hanging on for us makes sense. I think there is much truth in that. He's been like a little shadow following me around and sitting on my desk while I work for the last 14 years and so it's been very hard to say goodbye. But at least he is not suffering any more. Thank you again for your messages. Best wishes.