Susan Boyle says being treated for exhaustion was the "most frightening experience" of her life.
The Scottish singing sensation was treated at The Priory Clinic after failing to win TV talent show 'Britain's Got Talent' in 2009 and admits she felt isolated at the London facility.
She explained: "I was exhausted, I needed somewhere to go to recuperate . everybody knows that I went to The Priory.
"It was a bit of a scare, a scary time for me, being in a place like that. Although very therapeutic for some people, for people like me it was very scary.
"I thought, 'I've nobody here I know, where's my family? Where's my friends? Do I have anybody left?' I wasn't allowed to see a television, or make a phone call. 'Where was everybody?' I just felt as though I'd been dumped, it was probably the most frightening experience I'd been through.
"I felt that the dream was over. A bit of a nightmare, but, a turning point. For two days I was thinking about myself, what my position was, was I stable? I knew I was, I was just tired."
The 'Wild Horses' singer also admitted she has a terrible temper, likening herself to giant green comic book character the Incredible Hulk.
She added in an interview with Piers Morgan: "I have got a temper, I'm like the Incredible Hulk!
"It is a defence mechanism it was my way of dealing with a whole load of tension, I was channelling it into the wrong things. I was letting off fire at everybody and I really shouldn't have been doing that.
"I think most of the time I was tired. I've learned to control that now."
The full interview will be aired on 'Piers Morgan's Life Stories' in the UK on Saturday (06.11.10) on ITV1.