hii can i ask something , if someone see this can u answer my question ?

hi @kyoash

that sounds like identity disturbance, which if you have bpd it's a pretty common symptom. They don't have nicknames but I do feel like there are different versions of me. Like a sad me, an angry me, an ideal version of me, an immature me etc. that feel like completely different people. Is that what it's like for you??

this article explains some theories: https://en.m.wikipedia.org/wiki/Identity_disturbance

Nick names sound like alters in DID. You might want to discuss it with your therapist about it. Good luck!~