Heather Rae El Moussa Says Filming “Selling Sunset” Was ‘Absolutely Brutal’ Before Being Diagnosed with Autoimmune Disorder

The reality star's recent pregnancy with son Tristan triggered Hashimoto's disease, a condition where the immune system attacks the thyroid gland

<p>Lisa O

Lisa O'Conner/AFP via Getty

Heather Rae El Moussa

Heather Rae El Moussa is opening up about the not-so-subtle symptoms she experienced in the lead-up to her autoimmune disorder diagnosis.

The reality star, 36, revealed that prior to learning that she has Hashimoto's disease — a chronic condition in which the immune system attacks the thyroid gland — she suffered intense fatigue. The exhaustion made filming her Netflix series Selling Sunset particularly challenging.

“I remember saying to my assistant, ‘I feel like I’m dead,'" El Moussa told Today.com. “My brain was so tired. My body was so tired. I was exhausted all the time, and no amount of sleep could make it better.”

She said she dreaded the days when she had to get in front of the camera for her reality show, which is set to premiere its seventh season on Friday. “Filming was absolutely brutal because I could barely get out of bed,” she recalled.

Related: 'Selling Sunset' Season 7 Sets a Premiere Date — Plus, See the New Cast Photo

El Moussa's symptoms first began when she was four months postpartum after she and husband Tarek El Moussa welcomed their son Tristan, now 8 months old, in February. Initially, she shrugged off her fatigue as a normal result of being a new mom with an infant still not sleeping through the night.

"I was like, I’m probably just foggy because of mom brain,’” she explained.

However, she also experienced a drastic drop in her breast milk supply. Her lactation consultant suggested she get blood work done, and she later received a phone call from her doctor, who determined she has the common autoimmune disorder.

<p>Courtesy of Netflix</p> Heather Rae El Moussa in season 7 of 'Selling Sunset.'

Courtesy of Netflix

Heather Rae El Moussa in season 7 of 'Selling Sunset.'

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Hashimoto's disease causes an array of symptoms including fatigue, weight gain, joint and muscle pain, and problems with memory and concentration, according to Mayo Clinic. Patients are typically treated with a synthetic hormone called levothyroxine, taken in pill form.

"When she told me what I had, I was in total shock," Heather recalled of her diagnosis, before adding that she is "feeling much better" now.

Heather is one of several celebrities — including Gigi Hadid, Kim Cattrall, Gina Rodriguez and Zoe Saldaña — who have opened up about living with Hashimoto's disease.

Related: Heather Rae El Moussa Shares ‘Bittersweet’ News She’s No Longer Breastfeeding Son Tristan: ‘I Love the Bond’

Despite the challenges, Heather told Today.com she managed to exclusively breastfeed Tristan for six months, something she is incredibly proud of. In addition to her milk supply issues caused by her Hashimoto's, her son was born with a tongue-tie, and had to undergo a laser frenectomy to fix the issue and allow him to better latch while nursing.

"We had a lot of things working against us, including my autoimmune disorder, but we did it," she said. "I’ve heard so many women say, ‘I only breastfed 2 months,’ and that makes me feel sad. Why ‘only?’ You should feel so proud that you even did it at all!"

Related: HGTV Renews ‘The Flipping El Moussas’ amid Heather’s Reduced Role on ‘Selling Sunset’ Season 7

In addition to a new season of Selling Sunset, Heather teased in July that her and Tarek's show The Flipping El Moussas will soon be returning to HGTV. In an Instagram post celebrating the news, she promised "an even bigger & BETTER season."

"The homes we’re flipping are crazier, we’re taking more risks, we’re being even more hands on with the design of each flip, we’re balancing our businesses with the kids and our newborn baby, and we’re bringing you along for the journey for ALL of the good, bad, or ugly," she wrote. "We can’t wait for you guys to see it so stay tuned and mark your calendars!!!"

For more People news, make sure to sign up for our newsletter!

Read the original article on People.