[Omroth]

If you haven't already, I would consider some less committal steps to find out more about the problem you're experiencing.

1. Take an unusually long time off - double whatever the most is you've taken in recent years. If you don't have the leave, call off sick. Keep a note of how you feel about work each day when you get up and when you go to bed.

2. Try to list what makes an unusually good day at work. Even in a very samey job there are days you travel; days you have meetings with specific kinds of people; days you work on something a bit unusual.

3. Consider finding a good (not always easy, but if you can afford it you'll have a much better hit rate if you go for min. £75 an hour) psycho-dynamics therapist. When "interviewing" them, say that your initial goal is to find out if moving jobs will make you happy.

What you do in your early thirties when you have the freedom and desire to instigate a big change could be very important, and it's worth finding out more about yourself to help make the right choice.