Hi and congrats on being there and then some!
As someone who made the jump one year ago (to the date no less!), I can relate.
Healthcare is a subject, I did worry about a lot and to some extent it is one of the few things that still worries me, one year in.
We are currently on an ACA plan that only covers us in our state (our state exchange does not offer any nationwide plans anymore). We supplement that by a very good travel insurance, as we are full time travellers and only plan to be in our home state a couple of months per year.
We also plan to use geographical arbitrage for non-emergency healthcare needs.
I think next year, despite all the unsecurities, we'll still be fine with that approach and then we'll have to figure out what to do in 2019 and going forward.
If there really is no other way, you can always go back to a part time job with health benefits in a couple of years, if you need to.
But until then you have had your FIRE experience and could enjoy your time.
In any case, congratulations on your achievement!! You are definitely FI, now you need to figure out if and how you want to RE, not a bad situation to be in!!