I (finally) just watched this movie.

Can anybody explain the ending to me? Like, I get that she was going crazy throughout the movie, but WTF at the ending?!?!?!

She was so obsessed with the Black Swan part that she really wanted to be the black swan I mean in real life and at the end she showed everyone that she can be or she is the real black swan which dies at the end. That's my interpretation.

She fell off a thing onto a mattress after the finale and bled to death because she stabbed herself with glass earlier

Her obsession with her role blurred the line between fantasy and reality, so as the film progresses, her life, reflecting the violent, chaotic nature of the Black Swan, just spins out of control. It's more of an artistic statement than anything else. We're not really meant to question how realistic it is but rather what her death symbolizes in the context of both her role in the play and her life.

But if you want a blunt, straightforward answer, she dies

She was as bored as I was watching the film and fell asleep.

She killed herself.

It shows her slowly losing her mind as she turns into the black swan leading to her killing herself. I have 3 theories on why she lost her mind.

A) She was schizofrenic and her mother tried to control it herself rather than take her to a doctor. It would explain why she lost touch with reality.

B) She was sexually molested by her mother. Repressed memories can do a lot to a child and it might explain her clear developmental problems. It could also be why she thought she saw her mother when she was in the bath.

C) She was raped. This might explain why she's so uncomfortable talking about sex and her fragility. It may also be why she's so dependant on her mother and her mother still treats her like a child.