Burnout often has more to do with how certain people cope than with how stressful life is. For example, it is more likely to occur in high achievers who put a lot of pressure on themselves to excel and who have poor boundaries with their work. Such people often struggle to accept things as "good enough" and typically worry about falling short if they are not on the top of their game at all times. They over achieve or "die trying."
Burnout usually builds up over time and, as such, can be easy to miss the symptoms until things get worse.
While recovery from burnout differs from person to person, a common therapy goal is to learn how to reprioritize to be more present-focused and appreciative of the here-and-now while having a healthier balance with the needs to accomplish and achieve. It is also necessary to learn how to be more effective at self-care.
If you'd like more information on how I can help you overcome burnout, please feel free to contact me.