Mike "The Situation" Sorrentino has reportedly fallen off the wagon. Us Weekly reported that the reality star, who went to rehab for substance abuse earlier this year, is drinking again.  A witness told the magazine that during a recent night out in Los Angeles, Mike was "downing so many cocktails, he could barely stand."  Insiders also say that he is under a lot of stress with Jersey Shore coming to a close. A source explained, "Mike's freaking out about what he's going to do after the show."  Mike's rep denied that the reality star is drinking. It's been reported that he stayed sober while filming the final season of Jersey Shore.