Speaking to the Daily Mail, the church worker from Blackburn, West Lothian, told of her struggle after mother Bridget died in 2007.
"After mum died it didn't fully register until maybe six months after. That's when the loneliness set in and there was nobody around except my cat Pebbles. When you lose someone as powerful as your mum you feel as if a part of you is taken away and that does things to your confidence,” she said.
"My confidence was pretty down at that time. A good way of levelling it out, I found, was to tell myself that even though she's not here physically, she is here mentally and spiritually. That's what keeps you going. I have my faith, which is the backbone of who I am, really."
She told the newspaper that at school she received the belt from teachers every day and was taunted by other students because of her learning disabilities.
"You're looking at someone who would get the belt every day. 'Will you Shut up, Susan!' - whack!"
She said she was “often left behind” at school and was a “slow learner”.
“I'm just a wee bit slower at picking things up than other people. So you get left behind in a system that just wants to rush on, you know? That was what I felt was happening to me,” she said.
She added: "There was discipline for the sake of discipline back then. But it's all very different now. I think teachers are taught to understand children with learning disabilities a lot better."
Boyle shot to global superstardom after her rendition of Les Miserable’s “I dreamed a dream” on Britain’s Got Talent impressed the judges and won the hearts of celebrities like Demi Moore and Ashton Kutcher.
Her debut album, I Dreamed a Dream, goes on sale next week and has already broken pre-order records on Amazon.
The album is being distributed to the Christian market through Integrity and is a collection of gospel and classic pop songs. It includes renditions of “How Great Thou Art” and “Amazing Grace” and a cover of the Rolling Stones’ “Wild Horses”.
Commenting on her choice of hymns, she said “How Great Thou Art” had “great personal meaning” to her because it reminded her of a friend who liked to sing it in church, while “Up to the Mountain” was a testimony to “reassurance, love and the ability to keep going no matter what ‘slings and arrows of outrageous fortune’ life throws at you”.
“God is our light,” she said.