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KRISTEN Stewart desperate to save her relationship with Robert Pattinson?

KRISTEN Stewart is desperate to save her relationship with Robert Pattinson.

"Kristen is desperate to keep Rob. She would do anything," a source said. "She's finally realized that she has nobody without him."

Kristen's been spotted out but is missing the British hunk.

"Kristen stepped outside to take a call from Rob, and when she came back in, she seemed really vulnerable and down in the dumps," said an onlooker who spotted the actress at LA hot spot Sassafras in February.

"Her friend, the singer Ellie Goulding, was there and tried to comfort her, but Kristen kept saying she was worried and didn't know what to do!"'

"Rob has been attempting to stop her from visiting [Australia] -- he told Kristen he wanted a break, and he wants to focus on the film," a source added. "But Kristen just keeps calling and texting. When he doesn't respond, she flies off the handle, so he just stops responding all together. They've gone without speaking for a week at times.