Emptiness for me is feeling like I don’t know who I am. Like if I could see inside the real me I would not recognize that person because I don’t understand my own identity.
I survive this by hiding.
My adult daughter with BPD survives it by pretending to be just like the person she is with. That serves several purposes for her. She gets to hide her constant identity crisis and also temporarily makes that person her friend, until they see her explode a couple times. Then they move on.
Anyway, I hope this helps.