I'm within a year of retirement and don't think I'll have any issues with mental health. First two jobs I had were ended with layoffs due to a sudden plant closure and a sudden bankruptcy, so I've always seen jobs as just 'my assignment for today, it may change tomorrow'. I never let myself get too connected to the companies or people where I work, and rarely discuss anything unique I do outside of work. When I retire I'll easily be able to leave it all in the past, don't see that I'll have any regrets, most of the major accomplishments I've had in life have been things I wanted to do outside of the work environment, and I hope to accomplish some more personal goals in retirement. As the Jack Kerouac quote goes:
Because in the end you won't remember the time spent working in the office or mowing your lawn, go climb that $%#&@% mountain.