The 24-year-old Italian was playing under the cloud of an unresolved doping case last year, with questions following him onto court and a feeling that other players were looking at him differently.
He successfully defended his title but later said he had considered walking away from the game.
Doping authorities ultimately ensured he had time away from the tour, giving him a three-month ban.
After returning to the tour, he won his first Wimbledon crown and went on to cap his most successful season with another ATP Finals title.
"Last year was definitely a much more difficult situation," Sinner told reporters on Friday.
"At that moment last year I didn't know exactly what was going to happen. I tried still to enjoy it when going out on the court, but you still have it in your head.
"It was difficult for me, but also for the family," he added.
"I tried to stay with the people I really love, which at times worked very well. At times it was a bit disappointing, too."
A year on, the four-time Grand Slam champion said the experience had matured him, giving him the ability to work his way through other challenges on and off the court.
"It got me even stronger as a person," he said.
"The person I've become is much more mature because I see things, when they're not going in the right direction, in different ways.
"Whatever comes on court, result-wise, that’s all an extra. I live the sport in a very different way now, which is relaxed, but I give everything I have. It’s a balance of everything.”
Second seed Sinner, who faces France's Hugo Gaston in the first round, is the favourite among bookmakers to win a third successive title at Melbourne Park, slightly ahead of arch-rival Carlos Alcaraz.
The duo swept all the Grand Slam trophies last season and few would be surprised if they meet in the Melbourne final on February 1st.
Sinner was beaten by six-time Grand Slam champion Alcaraz in the last major final at the U.S. Open, and left Flushing Meadows with the goal of adding more variation to his game.
He said on Friday he had been working hard on his physical endurance, tried a couple of things on his serve and worked on his transition to the net.
The adjustments were not just aimed at Alcaraz, he added.
"It's not just about beating one guy. It's more about feeling comfortable in every situation. That's what we tried to do in the off-season," he said.