Jersey Shore Gossip

(PEOPLE.com) -- The cast of MTV's "Jersey Shore" seem to everywhere nowadays, but one place you won't be seeing Jenni "J-Woww" Farley is the gym.

"I actually have not worked out since the show," she told PEOPLE Saturday, but added that she hasn't gained weight either.

So how has she managed to stay in shape? "I honestly think it's just sleep deprivation and just running around and being very active," she said while celebrating her 25th birthday at Las Vegas's Palms Casino Resort.

"I think I'm good right now," she said of her body. "I don't want to change that much for the second [season]. I still want to be myself, and if being myself is lazy, then that's great."

Far from lazy over the weekend, Farley was actively taking in all she could in Vegas, from sightseeing to clubbing. She even threw in a spa appointment.

Though her "Jersey Shore" costars weren't with her, she said several of them called to wish her well.

"The best one I got was from Snooki," she said. "She sang and said 'Happy birthday. We love you and miss you.' "