Hi Knitting. Obviously this is an old post and you may be (hopefully are) in a better placed now. I can't diagnose you either but from what you wrote it sounds like a lot of things I've read about quiet BPD. As far as the "splitting" goes, with quiet BPD you split yourself - not others. You think of yourself as completely worthless, without any redemptive possibilities. Like just about everything with BPD though, it's transitory. A fundamental tenet of BPD is the inability to maintain emotional states. They can change, literally on a dime.

I don't know where you are on your journey but I hope you are doing well.