Hestia Twilight--a time too short

I got her from a county shelter the end of October 2008. We had a little over a year together which was very good. She was a loving and happy cat, sleeping on me at night and in my lap during the day.
Then problems started. By April, she was responding very well to the Gargline insulin. But there were still other problems. For some, we found partial solutions. For others, not so much. And finally late Sunday she developed something major and I had to take her to the vet to be put down Monday morning.
Was the final thing fixable? I don't know. But I had reached the end of what I could do, both emotionally and financially. I feel very bad that I put her down mostly for my own mental health but in retrospect, I don't think she was all that happy. Before, she loved to be on top of me, in my lap or on my chest when I laid down. But for the last months, she became hypersensitive, wanting to be on me, but unable to bear it for more then a brief time. On my lap, she had to lie mostly on the chair with only a small part of herself actually on me. In bed, she could only lie near me and could not be touched. She became needy instead of loving. About two weeks ago, her voice changed, becoming deeper and louder. Something was not right.
As I was cleaning up the house late yesterday, removing tarps from the beds, finding and cleaning up more dried urine puddles under the bed, removing the baby gate from the other bedroom, opening the walk-in closet door, one of the other cats jumped up on the now un-tarped bed & I raced to remove him in case he was going to pee on the bed. That's when I it hit me how much strain I had been living with and how my trust was shattered. The other cats were happily using their litter boxes, all the messing had been her. This morning I found myself checking the house for poop or pee in the wrong places; a little PTSD, much?
I think she had been telling me, in one of the few ways available to her, that she needed to leave. And I think I knew that, at that deep unconscious level, but I was holding on and she was still somewhat undecided too. Until she knew for sure and told me for sure. But it still hurts, a lot.
I have to picture her with her own angel, with no other cats in the house, having a lap all day and a bed all night, snuggling and being loved and healthy.
She deserves no less.