If financially you can, then give yourself a break is my advice.
I've done 15 years in marketing (you might say serves me right!) and only enjoyed it/felt like I've fitted in for about 1 year of that total. It's taken its toll - signed off for stress once and nearly again this year, and now just been 'persuaded to leave' a job that ostensibly I'm well suited for but I just thought was ridiculously demanding, could have no impact and was, at the end of the day, meaningless.
Prob is, if you have that thing within you where you have a sense of adventure/ability to think for yourself and live outside the consumerist/social life/sit at a desk world that is seen as the acceptable norm, then it can be hard to feel fulfilled by the standard life.
I'm taking my recent experience to push for what I really want to do, before it takes too much of a toll. I recommend taking some time out as it really helps give you a broader perspective on what you can do to earn a living and how much cash you really do need.
Also, speak to friends and family who know you and will support you -they can be invaluable in providing insight and direction. Career coaches can be pricey but maybe a worthwhile investment.
I know it sounds a bit hippy but you have to be true to yourself...
This book too, highly recommended: How To Get A Job You'll Love by John Lees.