Two months before winning three Paralympic medals, Jessica-Jane Applegate could not breathe properly.
"It turned out that during training my throat was collapsing," the British swimmer told BBC Radio Norfolk.
The 20-year-old said she could not train and was worried she would not be able to compete at September's Rio Paralympics.
But after a career-saving operation nine weeks before the Games, she won two silver medals and a bronze.
Applegate had been struggling with breathing problems for more than a year that she put down to asthma or a chest infection.
"It got to the stage that I couldn't even train, I was just so tired all the time, and was stressing that I didn't even want to swim any more," the Great Yarmouth athlete said.
"I didn't want to carry on because I was just in pain, and I didn't want to swim if I couldn't swim very well.
"I didn't want to be anywhere near a swimming pool because it was stressing me out, as I only had Rio around the corner."
Applegate, who swam in the S14 Paralympic classification for those with an intellectual disability and won a gold at London 2012, had breathing problems when she was younger before they subsided.
The speed she was swimming at and the pressure of the water caused her throat to, in effect, collapse.
It meant Applegate, who also competes locally in able-bodied events, needed an operation to solve the laryngeal problem.
"I really didn't think I was going to be [in Rio], which made me very sad because I'd put all this hard work in and it wasn't even worth it, everything had just been binned," she said.
"I had to make the decision to carry on as I was or just put my health first and try to be able to breathe in the pool."
Despite overcoming this adversity, the competitor in Applegate was still disappointed in her result.
"I just really like winning. I was absolutely gutted when I didn't get at least one gold medal, but I obviously understand that I couldn't," she said.
"My drive is winning, winning anything, even beating my team-mate in the pool at training, who's a boy.
"It just feels great when you know you've worked so hard for that one moment, and that feeling at the end is brilliant."