Ailing Janet Jackson cancels more concerts

The doctor has again ordered Janet Jackson to postpone a return to her "Rock Witchu" tour.

Jackson was scheduled to resume her tour Monday night at the Turning Stone Resort in New York after canceling a show over the weekend in Connecticut. A message posted on the resort and casino's Web site stated the show had been canceled at the advice of Jackson's doctor.

She has since postponed several shows, including Thursday night's show at Madison Square Garden in New York. Promoters say the dates will be rescheduled.

No one is saying what is ailing Jackson, who was rushed to a hospital in Montreal before a concert in late September.

Jackson is on her first North American tour in seven years.

janet doing what have you done for me lately into Feedback:

Janet Jackson - If - Live - Rock Witchu Tour:

Janet Jackson has been released from the Royal Victoria Hospital in Montrea

Janet Jackson has been released from the Royal Victoria Hospital in Montreal, according to a hospital rep.

"Yesterday evening she was checked into the Royal Victoria Hospital and left a couple of hours later," Rebecca Burns, the spokeswoman for the McGill University Health Centre, which operates the hospital, told PEOPLE



Jackson, 42, cancelled her show in Montreal on Monday and was taken to the hospital after she "got suddenly ill" during her sound check, according to a statement from W&W Public Relations.



Further details of the singer's condition were not immediately available, and reps for Jackson did not return requests for additional comment.



Jackson kicked off her Rock Witchu tour promoting her latest album, Discipline, in Vancouver on Sept. 10.



Jackson has complained of exhaustion, a source close to boyfriend Jermaine Dupri tells PEOPLE. "A 42-year-old body can't handle what a 22-year-old body can," says the source. "I can tell you that she's definitely tired. It was probably exhaustion. She is doing back-to-back, three-hour shows, and her body isn't the same as it used to be."



The same night that Jackson was rushed to the hospital, Dupri was spotted in New York City partying at Patron's Music in Motion Tour featuring TI at Marquee. "If [Janet's condition] was more serious he would've rushed to her side," added the source.



Jackson is due to perform in Boston Wednesday night.



See the Video: Janet Jackson Hospitalization before Concert