So much torment & anguish for such a brief pay-off. All the visual cues & plot devices from the genre of "literature for people who enjoy suffering" are there, but none of the depth & detail. If that's your thing then this will pull all of your heart strings & you'll come out of it suitably harrowed. But for the rest of us, who worked this stuff through in our teenage-angst years, (other than depression) there's just frustration in the lack of characterisation. This may be intended, to show exactly how self-centred she is, but even her character isn't convincing, & the mother, artistic director, & arch-rival rôles are painfully thin, relying solely on the prompts fans of misery will already be familiar with. And the male dancers, without whom Swan Lake wouldn't have a story at all, may as well not exist.
All this doesn't mean it's a bad film, but it's just a cash machine to make money from fans of a genre, like so many horror movies. It doesn't advance the medium one bit, & certainly won't make anyone happier except those who profit from it.