Jan, I am so sorry to hear about losing Bonnie! But please try not to blame yourself or question any of your actions. Everyone (including you) knows that you only had the best intentions for her to have a happy, healthy life. Some things simply can not be foreseen.
I know that you will miss Bonnie, but she had YOU to love her, so she had a wonderful life.
RIP Bonnie. Run hard at the RB as a healthy cat who will wait for the day of reunion.