So...........There's a theory, probably incorrect, that there is a secret 7th episode that is supposed to air Sunday night, revealing that the last episode was all a dream of Bran's. I'm really hoping this is true, but most of the other theories have been wrong, so I don't have much hope. It would be risky for HBO to do, since I'm guessing a bunch of people ended their subscriptions Monday morning after the 6th episode aired, but it would be the mindfuck that was so desperately needed in Season 8.
LINK to the article