Sinead O'Connor, 45, who recently made headlines for her 16-day marriage to Barry Herridge and her public struggle with bipolar disorder, has canceled her upcoming tour due to feeling "very unwell," she announced on her website.

"As you all know I had a very serious breakdown between December and March and I had been advised by my doctor not to go on tour but didn't want to 'fail' or let anyone down as the tour was already booked to coincide with the album release," O'Connor wrote, referring to her ninth album, How About I Be Me (And You Be You?). "So very stupidly I ignored his advice to my great detriment, attempting to be stronger than I actually am. I apologise sincerely for any difficulties this may cause." The message appeared only for a few minutes, before O'Connor's website and Twitter account were made inactive, according to Billboard.

O'Connor was set to perform in U.S. locations Milwaukee, Boston, Washington, DC, Chicago and New York City. She says she still hopes to play this July at a Curtis Mayfield tribute concert in New York, reports The Washington Post.

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