Sounds like you were mortally wounded wherever you were before. You were snatched away your world, healed of your injuries, and left here. You're one of many who have been taken from our normal lives. Nobody knows who is doing it, or why. We also never know when we might be sent back to the very same moment from which we were taken.
It's a lot, I know. Just accept that you're here, that you're alive, and you will eventually return to your previous life.