FIRST PIC: Sad Kristen Stewart Steps Out for First Time Since Affair Scandal

USMagazine, Wednesday, August 22, 2012, 3:30pm (PDT)

Kristen Stewart finally came out of hiding in Los Angeles Aug. 20.

Looking somber, slim and exhausted, Stewart stepped out for the first time after she was caught cheating on her boyfriend of three years Robert Pattinson, 26, late last month. Wearing a backwards baseball cap and sunglasses, the 22-year-old Twilight actress showed off her toned abs in a white crop top, but kept her head down, holding a McDonalds coffee cup as she walked to her car.

PHOTOS: Kristen cheats on Rob -- all the shocking photos

"She isn't sleeping and she stays up all night-crying," a source tells the new Us Weekly, out now, of Stewart. "She's close to a total meltdown."

On July 24, Us revealed exclusive photos of Stewart engaged in a steamy makeout session with her married Snow White and the Huntsman director, Rupert Sanders, 41. Since then, she's stayed out of the spotlight, splitting her time between her parents' home in L.A.'s Woodland Hills and the Burbank, Calif. digs of her best girlfriend and Runaways costar Scout Taylor-Compton.

"She wants desperately to fix things and undo the mistakes she's made," a source of the actress recently told Us.

PHOTOS: Kristen and Rob in happier times

Proof that she's missing Rob? The actress was wearing his Orioles baseball cap and still wearing a gold ring on her finger, a previous gift rumored to be from Pattinson.

During a June interview with Elle magazine, Stewart opened up about the gold ring. "Everyone wants to know. Everyone knows already -- it's ridiculous."

PHOTOS: Kristen and Rupert's road to scandal

The actress won't be attending upcoming Twilight conventions -- and neither will her costars Pattinson or Taylor Lautner, 20. But she will be stepping back out on the red carpet in September to promote On the Road at the Toronto International Film Festival. Promotions -- and, presumably, red carpet walks worldwide with her costars -- will begin in three months for the final Twilight saga film, The Twilight Saga: Breaking Dawn - Part 2, which hits theaters on Nov. 16.

For more on how Stewart is coping after the scandal, pick up the new issue of Us Weekly, on stands Friday!

This article originally appeared on Usmagazine.com: FIRST PIC: Sad Kristen Stewart Steps Out for First Time Since Affair Scandal