e know it's hard being in the limelight, but these stars just can't seem to catch a break-or get it together.   Everyone was completely grossed out when photos of Britney Spears coming barefoot out of a public gas station rest stop were published. But most recently, Miss Brit pulled a Michael Jackson baby blunder and was caught driving with her son, Sean Preston, perched on her lap rather than strapped into a car seat. Ouch. Spears said in a statement that she did it because she "was terrified that the physically aggressive paparazzi would put both me and my baby in danger."   It seems One Night In Paris may get some competition. A 1999 sex tape featuring rap-rocker Kid Rock, former Creed lead singer Scott Stapp and four female fans on a tour bus was recently released on the Internet. Luckily, Kid Rock put a stop to the tape being released by a California company. We're guessing Stapp's new wife, former Miss New York's Jaclyn Nesheiwat is not impressed with this or his recent arrest for public intoxication at an airport en route to their honeymoon.   Tom Sizemore has been ordered back into rehab and sentenced to three years probation after admitting to using drugs last month. The Saving Private Ryan star had been making progress after being caught last July using a prosthetic penis sewn into his boxer shorts and filled with a clean urine sample, to fake drug test results. The actor is required to undergo random drug tests as a condition of probation for his convictions on separate charges of methamphetamine possession and beating his ex-girlfriend, former Hollywood madam Heidi Fleiss.