If I loved myself, I would stand up for myself, right? But, I just know that if I told her how she was making me feel, it would simply lead to another fit of rage.
I don't think it's a lack of self-love to not stand up for yourself. With my N/BPD SIL standing up for yourself, particularly in an emotional way, often leads to more confusion and chaos. Sometimes not standing up for yourself is just the path of least resistance. I agree that telling her how you feel won't help. A NPD or BPD sees the world through their own feelings. She most likely can't empathize with you, or even imagine how she looks through your eyes.
With a N/BPD I think it's better to not tell them how you feel or how they make you feel, but to tell them what your boundaries are, what is okay or not okay. If you need to tell her no, just say no and don't explain why. If she's being hostile, just tell her your willing to talk when she's ready to stop yelling. We walked on eggshells for years around my n/BPD sil. I wanted to be gracious and forgiving in everything I did. I wanted to treat her the way I would want to be treated. Looking back, I realize I didn't say no often enough. If I treated someone the way she treated me, I would expect consequences. She may not understand the consequences, but that doesn't mean she shouldn't experience consequences any way.
If you listen to podcasts at all, there are some really good ones that talk about boundaries with narcissists. I think it applies to NPD or BPD all the same.
Understanding Today's Narcissist is really good:
https://itunes.apple.com/us/podcast/understanding-todays-narcissist/id1209719013?mt=2I also like Terri Cole's Hello Freedom. She has videos and podcasts based on the videos:
https://terricole.com/videos/