Last month, Lewis picked up his first PDC ranking title in over three years with victory over Boris Koltsov in the Players Championship 20 final.
The 37-year-old has struggled for form in recent years and gradually slipped down the world rankings.
After claiming his second world championship crown in 2012, Lewis went on to win the 2013 European Championship and the 2014 Grand Slam.
The latter turned out to be his last televised title as Lewis gradually relinquished his place in the world's top 32.
Speaking on the latest episode of the Darts Show Podcast Special, he said: "Mentally it's tough. It takes its toll on you at certain times.
"When you're there, all you try to concentrate on is playing the best that you can, pick up as much ranking money as you can and keep moving up, rather than looking behind you.
"You live your life on a rollercoaster. You have ups and downs, and your family go through it as well.
"I always say if you play this game, you've got to be a sucker for punishment! You have to deal with it, try to put it behind you, and focus on what is in front of you."
Lewis has produced glimpses of his old form in recent months, and admitted there is still more to come from Jackpot.
He added: "I'm proud of what I have achieved so far in the game, but I know there is a lot more to come.
"I'd like to win the World Matchplay. The Grand Slam too, because I should have won it last time if Phil hadn't averaged 112 against me!
"As long as I can qualify and make sure I'm right for these events, I believe I have as good a chance as anybody.
"I've got another few years at it yet."