It is hard to tell... .but I understand the mess she is making in your mind. You aren't crazy that's for sure.
Sometimes I ask myself- "what would a 5 year old do?" -to explain a BPD behavior.
I love enlighten me's advice (always)... .it takes two.
What are you doing to take care of yourself? Do you want to recycle?
I just think living next to her that this won't be the end of it. Selling is realistically out of the question for now as I'd lose money on the property. I'm just trying to spend time with friends and family. If I'm in and I hear her in the stair I'm trying to ignore it, same with checking to see if her car is there. It's difficult, I know I'll probably see her with her rebound at some point.
With regards to recycling I want to categorically say no. I think I know too much about BPD now to think it would work. That said, I still have feelings for her and sometimes think if I could point her in the right direction she could start to help herself. She knows something is up with her but as far as I know ahe can't put her finger on it. I feel it's such a waste for a girl like her who, when lucid, can be very amicable.