That makes me laugh, been there. You could be the strongest guy she has ever met, have a BF of 5%, a body like a Greek God and because you share the same pillow with her, you're a dumbass!
Well from one dumbass to another, let her do her thing and keep your mouth shut, it will run its course. Just be happy she's doing something and who knows, she may start feeling better about herself. Maybe even good enough to put on that teddy she hasn't had on in quite some time.