Miranda Lambert** is as country strong as they come, but even she has moments of weakness.

In the February issue of Redbook, the "Fastest Girl in Town" singer, 29, opens up about what lies beneath her sweet and sunny exterior.

"I'm insecure about tons of things!" she reveals to the magazine. "I cry onstage once a week, singing 'The House That Built Me,' and I always tell the crowd, 'Don't tell anyone I was cryin'!'"

Another song that brings her to tears, she says, is "Over You," which she and hubby Blake Shelton** co-wrote about the death of his older brother. The tune carries even more significance now, ever since Shelton lost his father and Lambert lost her best friend and childhood pet in the span of two weeks in January 2012.

"It was really hard to get up there after we had been to three funerals," the Grammy-winning musician tells Redbook. "I went back onstage, and I wasn't ready, but the crowd just embraced me. I was like, 'Okay, I'm really real. Like, all of this tough-girl image? My walls are down and all these people can see it.'"

"It was a good moment for me," she continues. "I just laid it out there, like, 'I'm normal, I'm a girl, I have PMS, and I get emotional, and I'm sad sometimes, and that's it.' I feel like I got over the hump of trying to be like, 'I have a chip on my shoulder, I'm strong all the time,' you know? Because no one is."

That said, Lambert isn't one to back down from a fight. Last year, she started a brief Twitter war with Chris Brown**, after the R&B star was honored at the 2012 Grammy Awards.

"He beat on a girl...not cool that we act like that didn't happen," she tweeted of the "Turn Up the Music" singer, who assaulted on-again, off-again girlfriend Rihanna in 2009. "He needs to listen to 'Gunpowder and Lead' and be put back in his place. Not at the Grammys." (Brown, for his part, responded on the micro-blogging site by accusing the songstress of using his name "to get publicity.")

"I didn't feel right about not saying something," Lambert tells Redbook of the now-infamous tweet. "The loudmouth that I am, I say what I think. I wanted everyone to know that I don't agree with the message it's sending to young women. It's not okay. At all. To be celebrated after doing something like that. I don't think it's right, I never will, and I will stand by what I said till the day I die."

Happily, the country star's own relationship with Shelton, whom she calls "the sweetest guy," is far less dramatic. Talking to the magazine about her husband of nearly two years, she gushes: "When I go to The Voice set and everyone says, 'Blake's been talking about you so much,' it just makes me feel special, you know?"

This article originally appeared on Usmagazine.com: Miranda Lambert: "I Cry Onstage Once a Week"