Survivor winner Kristie opens up about her "very, very intense" anxiety attacks.

On Tuesday night’s Survivor Australia finale, we learned that 24-year-old winner Kristie Bennett suffered from crippling anxiety attacks during her 55-day stay on the Samoan island.

What makes matters worse is the former senior account executive had no idea about her condition until she found herself in the most mentally challenging conditions of her life.

“I had no idea what was going on,” Kristie told Mamamia of her first anxiety attack, which she says was predominantly brought on by a lack of sleep and food. “On Day Three I just spun out.”

“My mind was so overwhelmed with everything going on. We hadn’t eaten or slept and I didn’t know what was happening.”

It wasn’t until fellow Aganoan and eventual second runner-up El Rowland found Kristie “curled up in the corner”, that the champion was told she was displaying classic signs of anxiety.

"I’d never had an anxiety attack before," she explained. "The attacks were very, very intense. I had two of them and they lasted for ten hours each. Now, I can’t remember the second or third day at all."

While fellow castaways who are well educated about anxiety, like El and Flick Egginton, helped Kristie, she says it was her most difficult internal battle on the show.

"I had been living with anxiety for the majority of my life and I didn’t even know it," Kristie said. "Everyone here was dealing with anxiety, but I was dealing with the fact that I’d had it my whole life and had only just found out.”

Kristie likened the transition from life on the island back to her everyday life to "culture shock".

“I had no idea about the aftermath [of the show]," she said. "All of a sudden you’re out of this thing that became your reality, and you're shocked back into your everyday life again, it's really weird."

While life has been frantic since Kristie landed back in her hometown of Sydney and demolished her favourite meal "Eggs Bennie", she has plans to discuss her anxiety with a doctor soon.

"I haven’t been diagnosed but I’ve been going a million miles an hour since filming ended," she admitted, adding: "I’m so interested in cognitive behavioural therapy and I’m trying to get educated about it.”

To read Mamamia's recap of the Survivor finale, click here.

If you or a loved one is suffering from anxiety, Mamamia urges you to contact Beyond Blue.