Is it normal for the pwbpd to accuse you of everything you say you are doing to her?
To answer your question, YES. It's so common that I could argue it could be one of the diagnostic criteria for BPD. In a nutshell, it's projection. In essence, your pwBPD is ruminating and worrying so much about her perceived flaws that they are always top-of-mind, and whenever she's upset, these thoughts emerge as projection onto you. She might project a mix of anger, fear, insecurity and/or blaming, depending on the situation. You can be certain it's projection when what she says about you is ridiculous and completely overblown. Like, "You're a lazy piece of s* who will never amount to anything, you're a horrible partner, you're psycho, you should be euthanized," when reality is, you work hard, you make good money, you take care of practically everything in the household, and you've gone above and beyond to take care of your partner. The other reality? Her words are really code for: I don't pull my weight, I'm a lousy partner, I'm mentally unstable, he's going to break up with me, I can't take this anymore, I'm thinking of killing myself, only death would put me out of my misery. She's ruminating about these thoughts so much that they are eating her alive. Since these feelings are too painful to bear, she needs an outlet for them, namely YOU. In the process, she blames you for "making" her feel this way. PwBPD have a victim mindset, and so they believe that other people cause all their ill feelings. In addition, she might try to "punish" you, and inflict pain, so that you have a glimpse of how horrible she feels. That's her maladjusted way of coping with life.
Now, I'm not implying you're perfect, because nobody is perfect. If someone is yelling at you and making accusations, what you might try is some silent fact-checking. Is this a valid complaint? Did you really do what they said you did? Or is the accuser jealous, insecure or under duress, using you as a punching bag, trying to exert control, trying to extract concessions, arguing unfairly? Are they merely projecting their own fears onto you?
I'm not going to lie, some pwBPD are smart and can figure out how to push your buttons. They rely on the FOG--your sense of Fear, Obligation and Guilt--to cloud your judgment. They might make insults or accusations that exploit a weakness or a gray area. But having said that, I think that once you understand projection, it's easier not to take everything to heart. Oftentimes, she seems unhinged. That's just the way she is, and it has little to do with you. You just happened to be the one closest to her, and so you're her punching bag. Does that make sense?