I believe it's probably something to do with the fact that you are not over the breakup with your ex. How long ago did you break up? Do you regret it and still have feelings for him? Do you desire for him to still love you? To me, that's what this dream suggests. I don't know what the lightning means, perhaps it is just entirely random. But the fact that your head reattached to your body and you came back from the dead because you said "I love you" suggests that you strongly desire to tell him that you still have feelings for him and by telling him you have become whole. I don't know much about you and your situation so the interpretation is more of a shot in the dark.