You're actually in a good field for someone who's decided that working in an office feels psychologically and physically unhealthy. You don't say exactly what you do, but as a whole, this sector lends itself to more flexibility than if you worked at a bank, for instance. Chances are good that you have writing skills, based on your background, which will allow you to work from anywhere -- you don't need to be hemmed in by four walls. So, consider yourself lucky on that score.
What you need to decide is how you'd like to structure your work life. It sounds like free-lancing might be the way to go, since you don't want to be tied to a traditional office environment. You'll have to make a trade-off, however. It's unlikely that you'll find a free-lance job that offers a lot of responsibility. In other words, your desire for change will have to be stronger than your fear of losing what's familiar.
Try to find three employers who need your talents so you'll always have at least one assignment in the works. You'll feel secure because you won't have to rely on one employer and can count on a steady flow of income. If you hold a bias that free-lancing isn't a respectable way to earn a living, get rid of it. Many talented people make their living this way. With hundreds, if not thousands, of publications in Europe, and opportunities beyond measure on the Internet, finding work shouldn't be a problem.
If you find that you can't make the kind of money you want, you'll have to readjust your priorities and decide what's more important -- money or a flexible work environment. If money comes out on top, you'll have to consider returning to a more traditional job.
Finally, consider working for a nonprofit organization a few hours a month. You won't get paid, but it will give you recognition for your contributions and a feeling of respect that may in the end be worth more than any amount of money.