The England international struggled with injuries in the 2021-22 campaign.
He shared the news on social media, urging young people not to suppress emotions.
“On a personal note I have had to dig deep within myself at times this season and have endured some of the most difficult times of my career and my life to date,” the 25-year-old posted on Instagram.
“The love and support helped carry me through.
“One thing I learned this season is that everyone in whatever walk of life is fighting battles you know nothing about, and there is no shame in finding someone to talk to and being open and honest with yourself about how you really feel.
“To all the young kings suppressing emotion I advise you to talk, to a friend, family member or someone that will listen, talking saved my life.
“It will make you realise things are never as bad as they seem, and you’ll discover that the paradox of true strength is being able to face your weaknesses.”
Calvert-Lewin missed a chunk of the season due to injury and was restricted to just 17 top-flight appearances for the Toffees.
He returned for the run-in and scored a vital winner – his fifth goal of the campaign – in last week’s 3-2 win over Crystal Palace which secured survival for Frank Lampard’s side.
“Finishing the season on a high meant everything to me, enjoy the break Toffee fans you deserve it,” continued his post. “May the pressure continue to be a privilege.”