Laura Crane was moments away from death after she contracted sepsis.
The "Love Island" star "didn't realise" just how ill she was until her mother forced her to go to hospital but she praised medical staff for her treatment.
Speaking on "Lorraine", she said: "I didn't realise how ill I was... I had this crazy high temperature and my heart literally felt like it was coming out through my shirt.
"My mum was luckily coming to London to visit me - because she thought I wasn't really replying to her texts - so she was coming up... and if she hadn't of come, I wouldn't have gone to hospital that day."
"I couldn't understand how my own body had created it, [I thought] there must be something else.
"I've not had a definite answer about why I got this, because I had what I thought felt like bad period pains, I felt delirious the next day and had no concept of time. But the NHS were incredible, they instantly knew something was up."
The 23-year-old surfer admitted that the most terrifying moment about the ordeal was when her "heart rate couldn't really stabilise" and explained that she contracted the condition due to an infected cyst on her ovary.
She said: "The first five days I was in hospital they were trying to figure out where the infection was.
"I actually started to get worse and my temperature would go really high and then really low... and my heart rate couldn't really stabilise. That's when it got really scary when I thought I'm completely out of control of my body.
"In the end it was actually [down to] a cyst on my ovary and one of them became infected and became an abscess and they had to drain it. It was an ordeal!"