She finished in sixth place before finishing in fifth in the 50m freestyle just days later.

At the time she told reporters it was "possibly the greatest choke in Olympic history" and took a break from swimming to re-discover her love for it again. 

Campbell is back better than ever taking home three gold and two silver medals from the Commonwealth Games in April before breaking five Pan Pacs records for five golds last month. 

But now, over two years since the Rio Olympics, she has penned an emotional letter on to address the "keyboard warriors" who put money on her and judged her after failing to place.

"The sure bet (as many of you have subsequently told me “I lost money on you!”), I was the all but guaranteed that Olympic gold medal," she wrote.

"It would be another gold for the Australian medal tally, another reason to gloat to your Pommy friends, another reason to down that can of XXXX gold.

"But I was also just a person. And as it turns out, I wasn’t the sure bet. I wasn’t a contributor to Australia’s medal tally."

The "choke" as Campbell refers it to, took a long time to process but the words of disappointment she received from trolls, didn't compare to what she felt. 

"You could not have been more ashamed of me than I was of myself. You could not possible have judged me harsher than I was (and to an extent still am) judging myself."

"In saying that, I did feel your disappointment, I did feel your shame and I felt your judgement."

Being an athlete isn't easier, it takes years of sacrifice for less 60 seconds to either podium or wait another four years for a chance.  

While many were critical of Campbell's performance, she thanked those who believed in her when she didn't her self.

"In the months following Rio I am so immensely grateful the many thousands of messages of support I received. For the people who believed in me when I no longer believed in myself, thank you."

"Thank you for your kindness, your understanding and for seeing qualities in me that I could not and sometimes still struggle to see."