Burnout is not a place. It's a state of mind.
Burnout can happen to anyone. It can happen anytime, any place, at any pay rate.
No one is immune to burnout... Well, unless you don't have enough brain to grasp the concept of fast food. Then you're probably ok. But I digress.
There are several different levels of burnout.
1st Degree Burnout
Characterised by periods of listlessness and apathy, coupled with an inability to concentrate and a feeling of helplessness about your situation. Can usually be cured by a week or two of vacation and work enviornment changes. Drunken weekends are a stopgap solution, but the effect tends to not last longer than a week or so. Weekend warrior cases are often sufferers from first degree burnout. Ignoring the situation can lead to
2nd Degree Burnout
Increased listlessness and apathy, interpolated with periods of heavy frustration and anger. This is usually accompanied with a feeling of being trapped and an intense need to leave the situation. Second degree burnout is generally what people think of when they say 'burnout'. Long vacations, therapy and lifestyle changes can help with second degree burnout. Prolonged second degree burnout can lead to the incurable
3rd Degree Burnout
Deep depression, anger, violence toward inanimate objects. All the previous symptoms, but in much greater amounts. There is no career cure for 3rd degree burnout. This level of burnout is so severe that the subject can no longer cope with his or her work situation, or even his career choice. Often the mental balance is disrupted to the point that periods in mental hospitals, or years on a beach in tahiti are the only solutions. Almost without exception, the career of the subject in a particular field is ended completely, without hope of recovery or reentry. The subject is then required to switch careers in order to function. Unless (s)he has enough money amassed to just say screw it with the real world and node for the rest of his natural life.
On a personal note, I'm currently suffering from second degree burnout, or perhaps even a touch of third degree in terms of Systems Administration. It's not fun, it's not pretty, and it's exacerbated by the fact that, by it's very nature, sysadmin is a thankless, crappy salary type of job. As a result, I'll be going back to school full time next semester and working very part-time doing something where I don't ever have to take work home, or work more than 15 hours a week, or stay late.
If you see yourself in any of the above descriptions, GET HELP NOW! Or you will lose any love of life you may have left.