I don't know about for you, but for me, your second paragraph describes exactly the way I felt about myself before I was diagnosed. Holes in my memory, telling people very contradicting things, being spacey, all sorts of people saying hi and talking like they knew me when I swore I never met them in my life, unexplained physical sensations. I have a dissociative disorder and for me I experience a little bit of everything. I have parts. Some people use the term "alter." Everything I constructed was a way to cope with (and thus survive) trauma.

Dissociative disorders (there are several types) cover many things. If I had to summarize, people with dissociative disorders have all invented their own ingenius ways of altering reality so that they can escape trauma. Even after the trauma is past, the habit of altering reality remains. This can be done by switching personalities for different situations/triggers/groups of people/etc, believing the world is not real, believing you are not real, "just blanking out," living in daydreams/fantasies, etc.