The actress admits she started to lose her cool after the media took aim at her for dating married U.S. actor Balthazar Getty - and the final straw came when she and her mother had to scrub the word 'Slut' from outside her home.
She tells the new issue of Nylon magazine, "I got to a point where I was like, 'I will just run away.' It was just breaking my spirits, and I had been pretty resilient for a long time.
"I was not able to leave the house and was living in a state of fear, when I'm really a fearless person. I had a kind of semi-breakdown... and everything just became too much. It was cutting me up to the point where I thought it wasn't worth it.
"I thought, 'Either I try and take them on, or if I can't, I don't do this anymore.'.
Miller found a move away from London was just what she needed, and she now lives in a 16th century country cottage.
The Alfie star adds, "Things are calmer now. I'm not rebelling against something every day anymore.".