KCavallari112109_09_X17.jpg What the Hills?!

A source for Us Weekly says that during a party in Miami over Super Bowl weekend, Kristin Cavallari was "wasted the entire time" and "going around to everyone, asking them to score her some coke."

Though Kristin's lawyer denies the allegations, sources close to the reality TV starlet say that her hard-partying lifestyle is taking a toll on her. "Her issues are becoming apparent to everyone," a source says. "She's getting scary-thin and not showering regularly...She's clearly unhealthy."

While MTV declined to comment on the matter, a source close to the show said, "Her drug problem finally became an unavoidable conversation topic on film. If MTV uses the footage, it will be clear to everyone."

Hills co-stars/friends Brody Jenner, Audrina Patridge, Lo Bosworth and Stephanie Pratt have reportedly urged her to go to rehab, but "she doesn't think she has a problem," the source says.

Do you believe this!? She doesn't seem like that much of a mess lately, but maybe she's doing a good job hiding it?