What'd I actually do? Found a series of startups, none of which went anywhere. Fiddle around with technology, and learn some new technologies. Fret about how I wasn't being productive enough. I didn't read all that much - I read much more when I was in college. I got out of shape.
I have a friend who retired at a similar age who said "One of the worst parts about having money is realizing that most of your problems were not because of money in the first place, and then having to face them." Retirement removes a lot of constraints, but that also means that if you're still unhappy with your life, it's because of you and not your boss or employer.
