So, funny story, therapy first helps you identify the 'false'/'imposed' self and you get to the core of your underdeveloped true self, and that's where you hit a g-damn wall! I keep trying to build some sort of personality in an instant, staying up all night searching for some sort of a self...

And asking for advice is catch 22 - people with BPD just plain don't know while everyone who has actually managed to get a grip and develop some sort of self and no longer meets BPD criteria just sounds condescending and out of touch with how BPD feels (don't mean to be rude to these people, just sharing how it feels).