Retire. I'd buy myself a hundred acres or so here in Indiana (probably not for you, but I like quiet), make a lazy 3-fund portfolio (
https://www.bogleheads.org/wiki/Three-fund_portfolio ) with a million in each fund, throw another million in a robo advisor and leave whatever was left as cash. I'd never have to work again, I'd have many times my FIRE number.
Then schedule a physical, an optometrist appointment if you wear glasses/contacts and a dental checkup. You now have time to be mindful of your health.
Then I'd just take a few months off. Do absolutely nothing. Just relax, think, recharge.
Then I've always got a bazillion ideas I want to pursue, I"m sure you have some too. I'd probably start working on the idea I'm currently waiting to hear back from YC for the winter 2019 batch. I could spend 20-30k of my own money collecting a lot of data and quietly looking for a key person or two to help me with the project and I might actually pivot and go more of a non-profit route with the idea.
You do you though, just be sensible about it.
Read about the Trinity study https://www.bogleheads.org/wiki/Trinity_study_update
Basically, if you put some money into a lazy three fund, or just a broad market/whole market fund you can likely retire and withdrawal 3-4% of the initial amount for the rest of your life depending on your risk tolerance. If you just did 3 million like I suggested above if I were in your situation, you have 90-120k a year to live off of relatively safely.
If you move somewhere with sane housing prices, pretty much anywhere in the midwest, you can live fantastically wealthy off that as the median household income in the country is 59k.
What I'd also do is take a small percentage of the money, maybe 50-100k and go Brewster's Million(s). Go spend it on something fun or goofy, something you've always wanted or wanted to do but could never justify. Get it out of your system. Something like these vacation experiences (secret agent for a day, vomit comet, shark diving) or buy that car you always wanted, or take a 700-702 AD French drunken pottery spinning while standing on one leg while singing Won't You Be My Neighbor class that you thought would be fun.