ABC News' Abbie Boudreau reports:

Molly Sims is known for her bombshell model looks but after gaining 72 pounds while pregnant with her first child, son Brooks, born in June 2012, Sims was left with pounds to lose and an uncertainty that she would ever get her pre-baby body back.

"I actually have a picture of my scale and my feet and it was 204 pounds," Sims recalled to ABC News.

Six weeks after her C-section, Sims, 40, hit the gym to start losing the weight.

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"I would workout for an hour and 45 minutes, an hour and 50 [minutes]," said Sims, who also would wear a trash bag to sweat more while she exercised.

With the stubborn baby weight not coming off, Sims wore a corset, tried acupuncture and went to a Chinese herbalist as well.

"My neck was….I looked like a football player," Sims said. "I kept asking people, I'm like, 'I don't feel right. Something's wrong with me.'"

"Oh, it's your hormones. Oh, you just had a baby. Oh honey don't worry about it. You're in Hollywood and you're putting so much pressure on yourself to lose weight," Sims recalled of people's reactions.

It took four months after giving birth before Sims' intuition that something more was wrong was proven correct by her doctor.

"He was like, 'Uh oh. Something is wrong with your thyroid,'" Sims said of her doctor. "My neck was huge. I mean, literally, huge."

Sims says she was diagnosed with thyroiditis, an inflammation of the thyroid gland, and began taking medications to regulate her hormones.

"My neck slowly started going down," she said. "It took a year."

Now Sims and her husband, producer Scott Stuber, are trying for a second child and she says she hopes her experience will urge women to speak up.

""My wish is that [women] don't stop asking people what's wrong," said Sims. "I tell these women, I'm, like, 'If you think something's wrong, ask a million people.'"

"Just don't give up," she said.