I've read/seen stories where it is mostly memories. There are many supporiting documents that describe how to remember these memories using hypnotherapy. You can also use meditation and try to discover your Akashic Records.
They were different bodies, but your soul was in them. They were different people, but all from the same soul. So it was you, in a different body. You can go to a psychic and they can tell you or you can do hypnosis to figure it out. It's all in your subconscious (the records), but your conscious has forgotten it.