Black Swan: Still Reeling From its effect!

The other day the Mr and I watched Black Swan and my stomach is still churning!! The story might be unique and the message stark but the treatment and the performances were, to my mind, far from what I expected it to be. Firstly, there was hardly a character which was shown to be 'normal' without any obsession. The dancer obsessed with perfection, her mother obssessed with the daughter, the dance director obssessed with his lead dancers, the friend obssessed with having a good time, the ousted dancer obssessed about her dance director....by the end of it, it was difficult to ascertain which obssession the film was dealing with. Natalie Portman had one studied expression throughout, both before and after she goes completely berserk. She is a stunning beauty and the story, on paper, is intriguing but the director has made a hash of it. The sexually explicit scenes can only serve as titilation and nothing more, although, they signify a sort of rebellion by the young ballerina to her mother's oppressive love and possessiveness. The dance master, too had the same expression and it isn't clear what he is thinking or what it is that he is after. all in all it was a dark film with actors not having a clue about how they are supposed to react to what was happenening and it leaves you with a bad feeling in the mouth. Can anyone tell me why it was such a hit with everyone else??