The 26-year-old singer suffered from debilitating anxiety that left her struggling to leave the house so she's grateful she had an outlet in her music to help her pour out her thoughts.
She said: "Writing it down really helped,. I'm so lucky that I'm able to write my thoughts in songs. I think without that I would have been a recluse. I don't know what I would've done with my life, to be honest.
"I think the songwriting has helped me so much, so that's why I say to people: if you're too scared to go to someone or worried about what people are going to think about you, or [think that] are people judging you, just write a tweet, or write it on a piece of paper next to your bed.
"If you just write it down so it's in existence, there in front of you rather than just in your brain, it really helps."
The 'Perfect to Me' hitmaker's anxiety got so bad, she worried she wouldn't be able to perform any more.
She told the new digital issue of Glamour magazine: "In my worst moments, I'd think, 'Well, how am I even going to go on stage? How am I going to do what I do when I've worked so hard and for so long to get to this point? And now I don't even want to do it.' That was hard."
Anne-Marie sought various forms of therapy and found herself feeling much better when she was at home one day.
She said: "I think it was just one day around January 2019," she says. "I woke up and sat in my living room, and I felt like I was actually here and actually experiencing my experiences.
"I think it was after the hypnotherapy, after the learning that there is never a straightforward answer to how you get over it."
Read the full feature in the April Digital Issue of GLAMOUR, available online now.