Hi Easeful
I know exactly how you are feeling.
My AM (in her 60s) has recently disowned me essentially for confronting her about her alcoholism and introducing some personal boundaries that she didn't much like.
She is due to have a big operation shortly.
I worry about not being a good supportive daughter to her through her surgery. I worry about, what if she dies when we were estranged?
Yet -- she's the one that has disowned me! She has clearly stated our relationship is over, that I'm dead to her, and that I no longer have a mother. It's hard to believe this because it's so painful, which is when I get tempted to contact her and try to re-establish the relationship. I know I mustn't. But it's really hard - the guilt seems hardwired.
I agree with Best - you have been a wonderful daughter, going far beyond what many others would do.
I think the more you work on believing that, and on looking after yourself, the more the guilt-inducing power of the image in your mind will fade.