By peoplestaff225
October 02, 2009 04:00 PM

Milton Ventura/Celebrity Photo

While some celebrity moms appear to effortlessly shed their baby weight in a matter of weeks, mom-of-two Nicole Sullivan struggled to do the same after the birth of son Dashel Pierce, 2.

Knowledge is power, however, and as she awaited the birth of her second son — 4 ½-week-old Beckett Edward — the 39-year-old Rita Rocks star decided to chart a different course. To that end, Nicole recently signed on as the new face of Jenny Craig.

“I tried to kind of muscle through it [with Dashel] and a year later after having the baby I was still overweight, I still couldn’t fit into my jeans,” she explains to PEOPLE StyleWatch. “I was unhappy and I was mostly just disappointed in myself. I was down on myself.”

The wake-up call, Nicole says, came when she found herself avoiding certain situations with the kids for fear of being ridiculed. “There were these playdates, and I realized I didn’t want to go on the playdates because I didn’t want to get in a bathing suit,” she concedes. “And so I’m denying [Dashel] something that’s really fun and that made me feel horrible.”

Nicole says she also made the mistake of comparing her body with the bodies of other female celebrities. “I look at these [magazines] and they go, ‘She lost the weight and only three weeks later she’s in a bikini’ and I don’t understand that,” she confesses.

Click below to learn how much weight Nicole is hoping to lose.

Now that she’s returned to the set of Rita Rocks, Nicole says that she’s feeling a different kind of guilt entirely. “Welcome to the world of being a working mom,” she quips. “You’re not a card-carrying mom unless you’re feeling a lot of guilt.”

Vowing to take things “day-by-day,” Nicole says she’s hopeful her experience with Jenny Craig — with a stated goal of losing 35 lbs — will benefit Dashel and Beckett as well. “With…feeling better about myself, as time goes on, my energy will come back,” she points out.

As for life at home with two under three, Nicole is cautiously optimistic. “[It’s] better than I thought,” she says. Noting that big brotherhood is probably “stressful” for Dashel — “If I crawled inside his teeny brain I’m sure he’d be like, ‘What the…? It used to be just us and now it’s this guy,” she says — Nicole and husband Jason Packham are working to keep the mood upbeat.

“We try to keep a sense of humor. I turn the music on and make baby brother dance to hip hop and stuff like that, and move his arms, and that makes [Dashel] laugh,” she says.

— Missy with reporting by Katherine Kluznik Rentmeester