I'm glad you have a Pdoc (unto itself and also as opposed to psych stuff through a GP). I hear you on money. (The hours have gotten so bad where I am that my rent now exceeds my income(!) Yikes.) But there are usually some ways to work around that for therapy and the others mentioned some good ones.
There are quite a number of people here that have both the BP and BPD diagnoses, so whichever (or both) you have, you have company.

The important thing of course is what works in helping you, regardless of specific dx.
I don't have BPD, though my BF does. I've got BP, ADD and either (both??) GAD and/or OCD. I'm looking for clarification for my psych on the last two. (She'd said one then written the other on a form --not insurance-- and I'm not sure if it's a changed dx or??? -- so yeah, sometimes things aren't cut-and-dried and they're trying to work out what's going on with us.) Like you, I don't know others of my "kind" out in the wild

, so it's nice to come here where, regardless of how it shakes out, there are others who understand.