"There were tailwinds earlier in the morning but the wind turned right around for my race. Unfortunately these things happen," Pearson said.
"Two weeks ago in Perth I ran (12.73) and smashed three hurdles, so to come out today with a headwind like that and run times like that, I was pretty disappointed."
Pearson's extraordinary comeback from a spate of injuries to claim the world title in London last year makes her a red-hot chance to win her third-straight Commonwealth Games gold on the Gold Coast in April.
The self-coached 31-year-old's personal best remains the 12.28 she clocked to win her 2011 Daegu crown - a time that still stands as the world championships record - before claiming London 2012 Olympic gold in 12.35.
Her quickest since came five years later, a 12.48 at last July's London Diamond League meet a month preceding her 2017 world title in 12.59 on the same track.
Pearson admitted there was work to do to return to last year's form, less than three months out from her home Commonwealth Games.
That may include racing at next weekend's Queensland championships.
Either way, she was confident she'd improve.
"It's only January and I've got plenty of time before the Commonwealth Games," Pearson said.
"I'm going really well in training, obviously I don't peak for these types of competitions - we peak for the majors.
"All my build-up is going well, it's just a matter of putting out the races in times I like to see.
"Hopefully the times will come down, which I know they will.
"It is not a setback, these things happen, the human body does what the human body wants."