Wow, Swimmer! Those are odd comments, especially coming from your own mother!
Doubting your memory? I seriously doubt that. When someone says something so shocking and out of the blue, those things are burned into your memory. Could it be that someone (NM?) has invalidated your memory all your life that you doubt your own experiences? I can't count the times I have told my NM something she said to me or to someone else and she denies, denies, denies. So I began to doubt my own experiences as well.
Are these issues that she has - fears of schizophrenia, sexual abuse? Maybe that's why she brought them up. As a mother I can't imagine making the sexual abuse comment and then not following up - asking questions, getting help for my child. So it may have more to do with her issues.
My advice is to not doubt yourself. N's are really good at making us question ourselves, our experiences, our conversations, our very being. Until I learned about narcissism, I thought I was the oddball in the family. Then I found out about this, learned more about how to handle it, learned more about myself. I still struggle with painful memories, the envy of others who had parents who knew and acknowledged them. But now I know that my memories are valid and I am not the crazy person I believed myself to be.
Logy