I've had this happen to a friend. After some years toiling in obscure startups, he made his money, stopped working, bought a nice house, a nice car... And within two years was bored senseless. He joined a big company as an entry level SWE, not really caring about the money at all, but just so he'd have something to do with his time. A decade later he's happily retired but I think it took him some time to find a way to enjoy it.

Money buys you some freedom. Freedom to experiment, freedom not to stress out about making ends meet. The flip side of freedom is that it forces you to have to make weighty decisions.

This happens all the time, for example, when young people inherit fortunes. Some end up doing drugs and/or spending it all - this freedom can definitely wreck lives. One approach that I'm told can help is to define your values and live them out.

For example, you said you created startups. I assume it wasn't just because you were hoping for a payday. Was it because you enjoyed the creative process? Or was it because you wanted to help solve problems? Can you do more of this now that money allows you to?

Or, is your idea of a happy life centered in family, and in that case, what are you doing to start a successful one? Not that it's exclusive of other values.

But basically this freedom lifted your boat from being in the harbor where the channels it could go into were very clear, to being in the high seas where you can go anywhere. You're obviously in the fog. You now need to clarify your life goals to lift the fog, define where you want to take the boat before it bobs towards a storm. Good luck :) it's still a problem to solve but it's a good one to solve.

Recommend reading "Jackpot" by Michael Mechanic, which talks about how the "jackpot moment" affects people.