The Doctor sighs heavily and turns back around to face her. He has to be strong now. All he wants to do is run and hide. Hasn't he done enough?

"Nothing you can do? You can do something no one else on this ship can do. Accept me, River. Just how I am now. Don't try to mould me into the me you last saw. Don't try to fix me."

He wants to be able to be vulnerable, but he can't let himself do that if he fears people will try to fix him before he's ready. Or worse try to help him before they know anything about him.