Now you can either retire early and spend more time with your family, or, if you need something else to do, just get another job. Do volunteer work, become an activist for a cause you care about.
Free yourself from the worry and stress that comes with having to work for a living. You can still work, but do it because you want to, or because it's something you care about.
Paying off your mortgage is always a good idea too.
And you don't have to use any of this money. Feel free to be generous with it to others. Give to important causes, or to the homeless near where you live. Or sit on it. You wouldn't be the first person to turn out to have an unused fortune when you die.
Whatever the case, don't freak out about the money. Use it to free yourself from stress; don't make it a new source of stress.