Shocking details of Amy Winehouse’s drug use emerged Sunday night — including a report that she binged on crystal meth and may have brain damage after a 36-hour marijuana marathon.

The singer, 24, suffered two major overdoses, with such bad convulsions that they were “like a scene from 'The Exorcist.'”

And her body is so frail from drug use that doctors were scared she would break bones during a fit.

A close friend of Amy’s warned medics that one more overdose will probably kill her.

The friend revealed:

- Amy's first overdose in August 2007 was from cocaine, heroin, ecstasy, ketamine and crystal meth.

- She was advised to see a psychiatrist after displaying “multiple personality traits” that made her a suicide risk.

- Her second overdose was in July — when she inhaled an “inhuman” amount of marijuana that left her vomiting uncontrollably and hallucinating.

At the time, Winehouse's devoted dad Mitch, 54, said it was a “bad reaction to her medication.”

Medics are worried Amy’s brain was damaged by the cannabis overdose — she displayed symptoms normally associated with schizophrenia.

“The future is bleak, bleak, bleak," the friend said yesterday.

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