Jazzman-I send you my deepest condolences. It pained me to read your post thinking you may have turned your back on her. I am sure you have been there for her always. It seems that is just who you are.
I am so sorry for your pain but please don't go where you are going. It will only hurt you more and you know, deep in your heart, that you could not have done anything.
Be kind to yourself and remember that your love for her was the best thing you could give her.
Again, I am so sorry for the losses you and her family and friends are going through.