I am so sorry for your loss. It sounds like you had an amazingly fast connection and that you gave her all the happiness she could have in her last year. I put my Oscar down after watching him slowly become "not him" in his last month. He had lymphoma and he had surgery to remove a gigantic mass. However, the cancer was extremely aggressive and he didn't last much longer.
I got to say goodbye. My grief the few days after his death was overwhelming. I couldn't function at work and I felt sick with grief. My best friend was gone. I gave myself a change in scenery and some horse therapy. It has helped me tremendously. I still miss Oscar not being around, but I have hope that having another kitty will help me with the loneliness while also providing a home to a kitty who otherwise won't have one. I miss him terribly and I know I won't ever have the connection I had with him, but I'm hopeful that healing is there for me and that love is there for me. My pain was acute and my despair was great, but it would not have been so if I had not loved Oscar so much. I have to remind myself of that when I question whether I'd want to have another pet, potentially inviting that pain down the road. Given this horrible loss now, I still know that I'd do it all over again with him.
Oscar was but 9. I had not even 4 full years with him. He loved me so much. And I loved him. He is sorely missed.