"Right around Christmastime I was sitting in a parking lot and I felt like I just couldn't get out of the car," she tells Elle magazine about the moment of panic she experienced a month after the couple's breakup in October 2006. "It was like, I can't get out of the car."
Witherspoon, however, says she found strength in realizing that so many others have also made it through the pain of a divorce.
"I thought, Okay, half of the parking lot has dealt with this. More than half of the parking lot has dealt with this," she tells the magazine in its October issue. "Okay, let's make it a little bigger. Half of this city has dealt with this. Okay, let's make it a little bigger – half of this country, until I finally got out of the car."
The actress likens the memory to a scene from her Oscar-winning role in the Johnny Cash biopic: "There's this moment in Walk the Line where June Carter says, 'I was never aware of how much I was seen.' I was very aware of how much I was seen. It was this moment of self-discovery and loss of identity and who was stepping out of the car, you know? Who is that person?"
Despite Witherspoon's image of being a woman in control, the mother of two scoffs at the notion. "Oh, come on, man!" she says. "I wouldn't be able to do what I do if I were [always in control]. I wouldn't be able to have the empathy or the capacity to understand different lives."
Still, the actress, 31, prides herself on her Southern values – and not being like some of the other young stars making headlines in Hollywood.
"Everybody is hung out to dry now," she says of the coverage of young stars. "It's one thing if you're up for it and you want it, and you go out without your panties on. But if you're wearing your panties – gosh darn it, leave me alone!"