Dear Catherine,
I know what you're going through. We had to put our 18 year old cat to sleep last year and I still miss her. But it's sometimes the best thing to do, and from what I read in your story, you did the best you could and let your cat peacefully go away to a better world. Time heals all wounds, and the wonderful memories of the passtimes you had with your cat remain.
My deepest sympaties and condolences.

C.C.'s Mom