Ngl, I would have some pretty important existential questions in this situation, things like: "What happened to the me of this world, did you kill her and overwrite her with me? Did we swap without her consent? What happened to the me of that world, did I die when my consciousness transferred over? Is there another copy of me still living in that world feeling all of the pain and having no recourse?" It's very much a mindfuck when you really try to think about it.