"I went through a hard year and I'm not going to hide that," the 20-year-old Moretz told The (Australian) Daily Telegraph's Stellar. "I had to deal with this new level of fame while I was growing up, I was getting out of a relationship and all of it was very public. I wanted to hide."
Moretz said she went into "hermit mode" after the break-up. Her family helped her get back on her feet.
"They were like, 'That's all great that you want to go away — but you can't. You are your own person. You're going to have to deal with this sort of thing.' I felt like things were falling apart, like my head and heart weren't in the same place," the Hugo actress said. "Things started to change when I realised I have the power within to change them."
As Entertainment Tonight reported last month, Moretz and the 18-year-old Beckham got back together in late August. The oldest son of David and Victoria Beckham visited Moretz while she filmed a movie in New York and they went on a camping trip together in November.
Moretz's career also had a difficult year in 2017. She starred in Louis C.K.'s I Love You, Daddy, which was pulled from release after five women accused the comedian of sexual misconduct. Her other 2017 film, November Criminals, only had a small release this month.
She recently finished work on Suspiria and The Miseducation of Cameron Post.