Published Monday, 24 September 2012
The former N-Dubz star was left devastated in March when film footage of her engaged in an intimate act with her ex-boyfriend Justin Edwards circulated on the internet.
Contostavlos previously admitted the incident hit her hard, and she has now revealed she worried bosses of the reality show would sack her from the judging panel.
In her new memoirs, Honest: My Story So Far, serialised in The Sun newspaper, she writes: "It felt as though there was a massive axe swinging above me head. My job as a judge on The X Factor was to smile and be smart and funny.
"But underneath I was petrified of being made to look like some kind of slapper in front of the nation. I would try to put the whole thing out of my mind but it would all creep back - it was pretty much all-consuming.
"By this time, I'd suffered for months. I was moody and tearful, constantly afraid I'd get fired from The X Factor."
Contostavlos also admits she has yet to talk about the sex tape drama with her parents.
She adds: "I spoke to (personal assistant) Gareth and my lawyers, no one else. The thought of speaking to me family, my mum and dad, filled me with dread. I still haven't done that."
However, the singer is just eager to put the incident behind her: "I realised I had to pull myself together. I wasn't going to throw my life and career away over one setback."