It is interesting to hear your experiences and difference between BPD and DID. I don't have DID so I'm fully aware all my 'parts' are me. They don't feel like me when I'm in that state, I call them 'them' 'she' 'her' because they aren't me but they clearly are. I may feel i act in a way I maybe wouldn't if I wasn't upset or overwhelmed but take full ownership for how I act and apologise of any behaviour that may upset anyone, I do this most often with my therapist as that's where it happens the most severely. It happens outside of this too but usually I'll withdraw etc. I can describe those parts of me and they're very different but they are still me. I guess that's why the ANP-EPs idea makes sense. But I have a hard time figuring out if I'm me, if this is me or not. I don't feel authentic or whole. The me I talk about feels incomplete so that's why I feel I don't know who I am and sometimes I figure I am all of my parts too and people are complex and contradictory, I can love and hate simultaneously, that's normal. But what I don't get is how separate they feel and whether there should be a 'gap'. Plus I genuinely don't feel I'm my body. Even if I say this is me and that is them and talk about 'she' 'her' etc as if I know who I am, which means I must know to an extent...it is almost as though i know who I am because I know who I am not and yet they are me...so yep. That makes no sense!

I think BPD does have transitory dissociation in times of stress as part of its criteria and lack of sense of identity or self. I can't tell how that would differ from dissociation, I don't feel I change identity based on who I'm with because I'm still always me, but I feel split and as though there is no me also. I don't change to fit in with people but my moods change when I get upset etc. I can't tell what's a pattern of behaviour vs a pattern of feelings. I have similar reactions that repeat over and over in therapy... usually when I feel threatened or anxious. It's strange as I'll either shut down or I'll come out fighting!
I can see how BPD and dissociation have a huge overlap, I think DID feels more definitive so you lose time, you act dramatically different, i can't imagine that you'd have DID and either you not know it based on losing time or random things happening or someone saying you're different etc. A lot of my stuff is internal rather than external - although it does effect my behaviour in depression etc. Sometimes I feel I have so much emotional input my brain overloads and shuts down - that's what happens alot. I have lots of headaches these days.