The Girls Aloud star revealed in her autobiography Cheryl: My Story that she frequently broke down in tears and isolated herself prior to the finalisation of their divorce.
Cole admitted that she began to struggle after she publicly announced the split in February 2010.
"I just wanted to get out of the marriage and out of the house but as the day of the move got close I became more and more emotional," she said.
"I hadn't anticipated this. I think I was actually going through a nervous breakdown."
Cole continued to fulfil her role as a judge on The X Factor's live shows, but confessed that she felt like she was "cracking up".
She tried to keep herself busy, accepted a position on the US X Factor panel and prepared to move to Los Angeles in the hope of breaking the US market.
"On the face of it, I was coping," she said. "But I was still close to tears all the time. It was like my nerves were always close to snapping and I felt permanently on edge."
Cole also revealed that she felt distracted and distant throughout the UK X Factor final, despite her act Rebecca Ferguson finishing as runner-up.
"Inside I felt too stressed and anxious to enjoy the moment," she said. "Nobody could help me.
"'I'll be fine' I said. But really I wanted to say 'Help me, I can't live like this anymore. I'm miserable as hell'."
Cole went on to spend Christmas alone, and said that when she received a text message from Ashley's mum that said his family missed her, she "sobbed uncontrollably" and "broke down completely".
"I'm sure I'd been having a nervous breakdown for months," she added. "I can see that now.
"[I went away] for ten days and that's how I was the whole time, sad and paranoid and a shell of my normal self."
Cole is currently playing dates nationwide as part of her 'A Million Lights' tour. Watch the lyric video for her latest single from the LP, 'Screw You', below:
Photo gallery - Cheryl Cole through the years:
Copyright: Rex Features ITV