I'm so sorry for your pain, but you're NOT alone. Your story reminded me SO much of my own. With my own mom who probably has BPD as well. The drinking, the long letters she'd write me EVERYDAY telling me how horrible I was and that I was abandoning her, the way she treated me when she didn't come first. She would completely ignore me for a week at a time. She would look through me as though I wasn't there....and I wonder now why abandonment and clinging to people is so centralized in my being, and how she got on my case for talking to people about it..."Don't ever tell ANYONE our personal problems". I am also quiet...can't even talk to my husband.
You are NOT alone... We'll make it through this together.