There's hope for you. I know a lot of people older than you are, they've shown me that 40 is a young age for a job change.

Maybe concentrate on minimizing the 'crazy' symptoms first. Once those are manageable your chances are greatest. Then think hard about what kind of work you really want to be in. You seem well-suited to self-employment (given the history of management, startups, etc.) so maybe that's the best road. If not, look to corporate ownership for stability while you build a better plan.

Good luck. Your letter has convinced me that you've got enough stuff on the ball to find a good spot.