It really depends on a number of factors and how severe the burnout is. If there are other factors involved (stressful commute, interpersonal problems), make sure you deal with those.

If the burnout is mild and you're just working too hard, the solution is to take a break and reduce your hours.

If you're starting to suffer from CFS, then the best solution is a long-term break from work, and a serious re-evaluation of whether you want to continue working there.