The star admits she was reluctant to stop performing any earlier for fear of letting their fans down - but White knew when her body had had enough.
She tells Britain's The Sun, "I was so tired and lost so much weight. I kept getting chest infections and I was on antibiotics and steroids. My body was like, 'Okay, screw you, you've pushed me too hard.'
"We should've stopped earlier but when there were 10,000 kids in Japan who want to see you, you can't let them down because you don't know when you'll be there again.
"The travelling was so exhausting, it overshadowed having a number one record. There were times when we didn't know where we were going next."
Jules De Martino adds, "It was a blur and we were holding on for dear life."