"I hadn't had any kind of formal training on how to deal with the media and stuff like that … there was a lot of surprises in the early days," Boyle recalled.
"I didn't really know what was going to happen. But I'm a bit more relaxed now, I take it all in my stride."
It was when the negative headlines were at their worst that Boyle's manager and publicist Nicola Philips stepped in and she has been by the singer's side ever since.
"I don't think anyone would when you're being publicly assassinated and being called names, no-one is going to deal with that well," Ms Philips said.
"Especially when you've come from a very provincial town in Scotland and you have spent your life in cotton wool. So it was dealing with that shock. Obviously it upset her like it would upset anybody."
Ms Philips also rejected claims that the life of a performer was too stressful for Boyle and she shouldn't be singing.
"See I completely disagree," she told Grimshaw. "She's always said in terms of nerves that anxiety, the nerves of performing is what positions her into the place to get on stage, it focuses her. She loves it and she has an amazing life."
Boyle said she has now learnt "how to chill myself out more" and her 2012 diagnosis of Asperger's was life-changing.
"That was a relief for me because for years I thought I had something a bit more serious you know so that sort of took it off my shoulders a bit," the Scottish singer said.
"You just have to make people aware that sometimes you have to go a certain pace and don't be too bombarded with things. At the very beginning I was very bombarded."
Boyle, who previously thought she had brain damage, decided to go public with her Asperger's in order to show others that there was no shame in the diagnosis.
"There's nothing to keep secret, there's nothing to be ashamed of, everybody has something, a flaw if you like. But you shouldn't be ashamed of it, it's something to bring out in the open and hopefully you help other people.
"I like to feel I've been a voice for other people who have been the underdog and I wanted to try and prove myself."
She is now returning to the spotlight after a few years off with a new album and plans to tour the UK.
Boyle came runner-up on Britain's Got Talent and scored a record deal, with her debut album I Dreamed A Dream becoming the UK's fastest-selling debut album of all time.
Five more albums followed and Boyle is now estimated to be worth over $36 million, however, she has retreated from the spotlight in recent years.
Boyle bought a $540,000 house in her Scottish hometown of Blackburn but continues to live in the council house that she grew up in.
The singer has been open about her battle with mental health and struggled with the media attention following her star turn on Britain's Got Talent.
"When I went down to London it became overwhelming. That's just an understatement," she told The Sun in April.
"You're sitting one day on your couch not knowing what you're doing with your life and suddenly you go into a competition."
