The 27-year-old actress developed holes in the wall of her gut and admitted her body was completely "f**ked up" two years ago around the release of 'Star Wars: The Last Jedi' as a result of the pressure she felt.
She told Britain's GQ magazine: "I saw a picture of me at the London premiere and I was so skinny and my skin was terrible...
"My body was just f***ed up. I got tests done and it turned out my body was taking in no nutrients. I was just like a little skeleton and I was just so tired. I was becoming a ghost."
Daisy eventually took a six-month sabbatical from work and enjoyed the relaxed pace of everyday life.
She said: "I just needed to be at home and chill the f**k out, honestly.
"Just being in London, it was so nice, not having to rush everything through. Like, I love washing my clothes - I love doing the wash - but when you're working tons, you've got to smash it all in one day.
"This was 'Oh, my God. I'm going to do a load today' every day. It was lovely.
"I started going on the Tube again. And I was like, 'You know what? The world didn't stop turning. It's really fine.' It was everybody else making me feel like this was terrifying that made it so terrifying."
The 'Murder on the Orient Express' star thinks she's found a balance to her life now and isn't afraid to speak out when she isn't happy.
She said: "For so long, I was so scared to say to anyone, 'It's not all good all the time.' Because you know what? It's not all good all the time. I can say that now. Say no. Now I think I'm very nicely balanced."
Daisy felt refreshed after her break and was excited to return to work on the final 'Star Wars' movie, 'The Rise of Skywalker'.
She said: "I was so healthy. I was so there. I was just enjoying it. With this one, I had such a great time."
See the full feature in the January/February 2020 issue of British GQ available via digital download and newsstands on Friday (06.12.19).