welcome... just a little bit of information....DID is a mental disorder where someone has many identities rather than just one (the person born to this body) example wit in me there was Amanda ( me- the one born to this body) then I underwent extreme trauma before I was 5 yrs old. this extreme trauma caused my (amanda) mind to dissociate (some locations call this splitting/separating) into many different identities Amanda, Rainy, Thelma, Sunny......though there was discontinuity (differences between the alters and I) for me reality testing remained intact, meaning I knew who I was and my alters knew who they were, what their jobs, purposes reasons for being was.

you stated your past therapist said you dont have DID... if you dont agree with that you can go through some special diagnostic tests that can tell you whether you have DID and what type of alter gregory is (there are many different mental disorders and many different types of alters that come with the many different mental disorders, plus hearing voices can happen with just about every mental disorder out there)

my point is the only way you will be able to figure out whether gregory is the imaginary friend you thought he was vs having DID is by contacting a mental health treatment provider and going through the testing process. the tests can be tiresome but going through them was well worth it for me and what helped was after being diagnosed my treatment was things like grounding, breathing, meds for anxiety/depression.....

my suggestion contact a treatment provider then can help you with this regardless of what /who gregory is and regardless of who/what the voices are.