Two other books that may be of interest to you are Feel Free by David S. Viscott and The 4 Hour Work Week by Tim Ferriss. I quoted a passage from Viscott's book in the What Have You Read Recently thread that is very relevant to the situation you described.
http://www.early-retirement.org/foru...ml#post1042819.
The feeling is not surprising at all. I recently spent over 3 months dithering over wether to quit a job that was so boring that I wanted to claw my eyes out every morning when I logged on to my computer. The problem with the job was that in a big company, as soon as the start up project had become a semi-success, they threw in everybody and his brother in law on the project, so what was a great project with an entrepreneurial feel turned into yet another white collar version of turning a bolt as a car passes by on the assembly line complemented by the ceaseless bickering of a bunch of insecure people posturing for their little slot on the assembly line. With that said, it still took me 3 months of figuratively clawing my eyes out to ditch the security of a boring pay check to do something on my own which despite modeling and researching repeatedly, talking to mentors who have done the exact same thing successfully, and seeing others doing the exact same thing as I'm doing it, still feels scary as hell.