I've never experienced that from depression, but I definitely know what it feels like to lose your former self. When the lunatic therapist/doctor induced a dissociative identity I totally detached from my former self. I left that office as a different person. Literally. Black to white. Fight Club....the narrator to Tyler Durden. Yin to Yang. Ryan to Danielle. Ryan disappeared. He died, and Danielle was born. If you can wake up in a different time...in a different place...could you wake up as a different person? I did.
Then Danielle realized that Ryan was still there buried deep inside. And then Ryan realized that him and Danielle were the same person. And then Dani was born. And now Dani is basically Ryan incognito. And everything is destroyed, and all is lost, and Ryan is just like, "WHERE IS THIS FUCKING BUS??!"