There was a "feeling" I had, at one point during the worst of the trauma, where I felt like I died. The feeling was complete with an out-of-body experience and the whole nine yards. I could never shake the belief that some core part of myself had died and I lost my identity during the process.
After years of therapy, I discovered that the core self (containing a big chunk of my identity) was only buried deep inside of me and was not dead. I began making a list of the things I liked, loved, hated and feared and began to get a better sense of who I am. Maybe this will help you too.
I understand the absent identity thing. I used to feel like I carried my dead self in my womb where noone could see her. The exterior me was just a shell. It was wonderful to discover over time and therapy that I wasn't dead just overwhelmed.
As for not recognizing myself in the mirror, it can be funny. I once picked up a really pretty pink ribbon for my ponytail only to confront in the mirror an old lady with short curly gray hair. Oh, Well....