The singer fell sick while the band was shooting fly-on-the-wall series The Wanted Life in Los Angeles earlier this year (13), and subsequently underwent surgery to repair a haemorrhaging vocal cord.
Sykes, 20, admits he felt poorly for much of the shoot prior to his operation, and considered walking out on the show so he could fly back to his native Britain.
He tells Britain's Daily Star, "I was really, really close to quitting and going home at one point. It was just too much. Everywhere I looked there was a camera, and I wasn't sure if I could deal with it. I was ill and shut away in my room and just wanted to leave. I got really, really homesick."