Kristen Stewart is Breaking Down After Cheating on Robert Pattinson

Unable to sleep, eat or keep herself from obsessively following a vicious Internet hate campaign, Kristen Stewart seems to be heading for collapse — or worse.

OK! NEWS: KRISTEN STEWART FLIRTATIOUSLY DANCES IN ON THE ROAD TRAILER

Hunkered down in isolation at her mother’s secluded home in Woodland Hills, Calif., she’s glued to her computer — using it to read all the awful things that people have been saying about her since it was revealed that she cheated on Robert Pattinson, her boyfriend of three years, with her Snow White and the Huntsman director Rupert Sanders.

OK! NEWS: RUPERT SANDERS SAYS AFFAIR WITH KRISTEN STEWART IS WORST MISTAKE OF HIS LIFE

“She is a complete mess,” one insider says. “Her stomach is so knotted up that she has no interest in food, and she hasn’t had a full night’s sleep since this nightmare began.” The embattled actress is in such bad shape that her weight has dropped to an alarming 98 lbs. “She spends her days in a darkened room, poring over love letters Rob wrote her and watching videos they made together,” the source continues. “and she’s said some pretty crazy things lately, like how she’ll die if he doesn’t take her back or how no one would care if she disappeared off the face of the earth. It all sounds like a cry for help.”