Soul singer Duffy was miserable and lonely after finding fame, insisting she was so homesick she cried herself to sleep.
The Welsh star became an overnight sensation after scoring a hit with her debut track Mercy, but she admits she couldn't cope with her gruelling schedule and pined for home while travelling around the world.
She tells Britain's The Sun, "I love my music and performing but some of the other demands terrified me. I am just a normal girl from Wales and always will be.
"I locked myself in my room and cried and I'm not usually that kind of girl. I am quite tough and can cope with almost anything but that time was horrible. I just wanted my mum with me. I remember feeling as though things were going to fall apart.
"I don't know if it was borderline breakdown - but it was a hard time."
Duffy admits she is enjoying life again after finding love with rugby player Mike Phillips and she's learned to take charge of her career.
She adds, "I'm never going to complain about what I have achieved and I am eternally grateful for my success but I think the workload at times was too much for one human being.
"But you learn to switch off and the more famous you get, you develop a coping mechanism - your boundaries close in to protect yourself."