FANTASIA HAD AN OVERDOSE OF ASPIRIN & SLEEPING PILLS LAST NIGHT!

Fantasia Barrino's overdose last night was caused by a combination of aspirin and a sleep aid ... this according to the "American Idol" champ's manager.

The rep just released a statement saying Fantasia ingested the medication after feeling "overwhelmed by the lawsuit and the media attention" surrounding her relationship with her on-again, off-again boyfriend Antwaun Cook ... who happens to be married.

The statement continues,"Last night, Fantasia was hospitalized. She took an overdose of aspirin and a sleep aid. Her injuries are not life threatening. She was dehydrated and exhausted at the time. Fantasia is stable now. She will be released from the hospital soon."

The rep also explains that Fantasia "believed" Antwaun Cook when he told her "he was not happy in his marriage [to Paula Cook] and his heart was not in it."

Here's the statement in its entirety:

Fantasia has always been an open book. Honesty, self-respect, and personal responsibility are values she wears proudly.

Fantasia believed Mr. Cook when he told her he was not happy in his marriage and his heart was not in it. She believed him when he told her he and Mrs. Cook separated in the late summer of 2009. She believed Mr. Cook when he told her he lived elsewhere.