Thank you Marie. I'm pleasantly surprised at the responses I have received today.
Sophie had a lump 12 months ago (breast). Having discussed all possible ramifications with the Vet, I decided that I would do nothing about it. Obviously everything spread, whilst I wasn't aware of it. She was absolutely fine (first class) until a week ago. Then I noticed her breathing was laboured. I had her x-rayed, etc etc. Her lungs were completely eaten up with the cancer - no wonder she couldn't breathe. On Thursday morning I expected she had a number of weeks to live, and I cancelled Christmas arrangements with family "just in case". That night she was so so very bad (struggling) that, against all my better instincts and wishes, I phoned the Vet and arranged to take her around there (he wouldn't come to the house). He said that she was, in fact, dying, and that she wouldn't last the night, but that she would have a bad time at the end. It was the only option left open to me to give her a peaceful end. We (husband and I) cried loudly and despairingly in the surgery, but we knew what we had to do, and it was done. I can't seem to get over the fact that I took her around there, though I said I would never ever condone such a thing. Yet, in the end, she was struggling to breathe and I couldn't let her go on. Gosh, I hope I'm not upsetting everybody with this - I'm just telling it like it happened.
I feel that she trusted me implicitly, loved me unconditionally, and yet I "did this" to her. Anyway, Marie, thank you for your kind thoughts and support.