I just told my mom that we were putting her in assisted living. She cried first and then she got mad and told me it was all about me, that I didn't care about her at all. I told her we would visit and her response was, "if you put me away, stay away." She is in mid to late dementia and getting to be too much for me.
I can tell you what my sister told me when I was caring for our 90+ year old mother: "Daughter guilt is worse than Mother guilt"
Meaning that as mothers we all feel guilty about one thing or another regarding the raising of our kids, but the guilt we feel about not being able to make our mothers happy is more intense.
Then we feel guilty about the resentment we feel!
I hope this will pass, you say she is well into the effects of dementia so hopefully, after the move she will settle down and not have such an extreme reaction towards you.
My mother was uncharacteristically angry and mean after we had to take away her car. But after 2 weeks that was all gone.
One technique is to blame it all on the doctor!
Elderly people respect physicians and are often hesitant to second guess them. If you say "Dr_____ told us you needed to be here for now" maybe that takes the heat away from you.
Please do not let this put a permanent wall up between you two. She may not have long to live, and I would hate for you to have regrets.
She knows you care, you have been caring. And now "following the doctor's advice" shows you are still caring!
Maybe before the move you can show her curtains or special pillow cases or something that she can chose to bring with her. Maybe giving her as many choices as possible will help her feel some control (just a choice between A or B, too many options can overwhelm). It may help.
I really hope this cloud passes. Best of luck,
Margaret