"Any journey down that road is not easy for a female, period," she said.
"But you just gotta do what you gotta do, and I'm cancer free forever – breast cancer free, at least, and that has been all worth the struggle."
The I'm Outta Love singer said she prepared herself for potentially having to undergo the procedure after she was first diagnosed with breast cancer in 2003.
"I had already thought, on my first go-around with cancer, if I got it again that I probably would choose a double mastectomy," the 45-year-old told Lorraine on Thursday morning.
"I think I kind of prepared in my head enough for that decision when it was the decision to make."
The songstress also praised her good friends Elton John and Sharon Osbourne, who also went a double mastectomy this year, for their support throughout the ordeal.
Anastacia and Sharon in 2003
"Sharon, Elton, they have been more than friends, more than respectful in just being teatime buddies," she said.
"I am so grateful that they find the time out of their crazy schedules to even care about how I'm feeling and what's happening with me. It means the world, it really does."
The One Day In Your Life singer also spoke about her forthcoming album and how the music became her medicine.
"I have to tell you, if I didn't have this album to do, it would be much harder," she said. "The cathartic, inspirational songs that have come about … my goodness, I am so excited!
"I was just in the studio today. It's hard for me, I don't want to talk about it and say that it is the best album in the world – but it is!"
The singer had been due to begin touring in London on 6 April but was advised by doctors to cancel the European tour.
"I feel so awful to be letting down all my amazing fans who were looking forward to It's A Man's World Tour," she said at the time. "It just breaks my heart to disappoint them."