It means you’re exhausting your employees either physically, emotionally, mentally or some combination of the 3.
If my employee told me that I would want to take a hard, and honest self evaluation of my performance as a manager. As a leader at work, it’s my job to empower and support my employees, so they can do their best work. In many ways, I try to set up a dynamic where I am frequently asking my employees if there are ways I can help/support them. They work hard and I empower them to make decisions. This keeps them happier and more productive than a top-down military style of leadership. The keys to productive and happy employees is autonomy, mastery and purpose. At the end of the day we generate more revenue, have lower turnover and have a more positive work environment as a result. That’s good business.
I should add, it takes a lot of courage for an employee to work up the courage to give you that kind of feedback. I hope you thanked him/her for doing so.