Many pwBPD suffer from low self esteem (some masked by narcissistic traits), but ultimately it stems from a core sense of shame. Guilt is, "I've done something wrong, here's what I'm going to do to amend it." Shame is, "I'm a bad person, here's what I'm going to do to cope," and cue many behaviors common with BPD, or anyone who feels shame, for that matter.
In talks with my T, the background I know about my uBPDx and also my BPD mom, I can see how shame drives many of their behaviors. It stems from an invalidating childhood, often growing up in households where one was not allowed to exhibit their feelings, or even more extreme, told how to feel. Now, many of us here also come from such homes, being one reason why many of us are attracted to pwBPD. My Ex was shamed, invalidated, and abandoned in childhood in a number of ways; my mother, far more horribly. I was shamed in many ways as a child, but not to the extent of losing my identity, though I only grew really confident, I think, by my mid 30s. I always knew who I was, however, I didn't know how to be.
We can't say exactly how a pwBPD feels, but can only surmise based upon our knowledge and level of empathy (which goes back to our own experiences). Have you seen this article by a member here who is a recovered pwBPD? Maybe it can shed some light for you:
BPD Behaviors: How it feels to have BPDTurkish
