Hi Jemimah
I'd like to join
Leaving in welcoming you here. Having a parent with a personality disorder isn't easy.
Has your mother always behaved in a way that you now would classify as BPD?
How often do you see her or speak to her on the phone?
Your post makes clear that her behavior is really taking it's toll on you. To help protect your own well-being, I strongly encourage you to take a look at some material we have here about boundaries and asserting yourself:
Setting Boundaries and Setting LimitsCOMMUNICATION: D.E.A.R.M.A.N. techniqueTake care and I encourage you to keep posting here