Touch the Sky - help plz
So I'm doing Dawngaurd mission Touch the Sky and I get to the end boss he casts some kind of spell and the Serana asks if I'm ok. Well I'm not, I can't unsheath my weapons, I can't shout, I at least can still move, I can't even access my inventory or map. It's like some of my keyboard inputs are blocked. And Serana is doing no damage at all to the end guy.
Any help please
Any help please