I believe a little therapist-guided soul searching is worth the money, especially if you're FI. That way you significantly reduce your chances of getting to the end with an empty, "Is that all there is?" feeling. Not saying you can't keep working forever, but it would be worth a little soul searching to get rid of your angst.
Ditto. This helped me to be able to take the leap.
I just made the FIRE decision, even though I have fears. Make friends with your fear and just work through it. A counselor will help.
Next week is my last day, and honestly I don't have all the answers yet... learn to accept that that's okay. I wasn't really in a position to try out part-time or a lesser role where I work (commute, corporate culture, and size of company were all barriers to that), but I came to accept that I really needed to step away from this phase of my life completely. I have technical skills (CPA, accountant) that I can find a home with somewhere else if and when the time comes.
Realize that if you've been able to get to this point you have the discipline and knowledge to do things that few people do -- save money, solve problems, live counter to the consumer culture. You do not lose those the ability to work through challenges the day you quit your job, and in fact, you may find that with fewer hassles, more time, and more mental bandwidth you can solve those problems creatively. You've been building your tool box for years.
My spouse is still working and has health insurance, but I honestly felt that we needed a less stressful period in our lives -- now that we've saved our FIRE target -- to learn to live a lifestyle closer to our FIRE lifestyle. I wanted to give up my commute and desk job so I can spend time walking and biking. I want to devote time to my religious community and to another non-profit instead of just throwing money at them. I need to do some soul-searching. That's impossible to do when you're on the hamster wheel, just getting by.
Bear in mind, that you're getting this advice from a very type-A, "gotta have my ducks all in a row," analytical accountant type... Sometimes you just have to step back and take a calculated risk. You can always find more money or reduce your standard of living. The only way to get more time is to FIRE.