@Murse, please keep in mind that nothing has to be permanent. What is urgent and a “hair on fire” emergency is your mental health and well-being. With the stash you have you can confidently quit work for one year, two years or more and easily go back to work down the line if you decide it’s necessary. Should you still struggle to actually give notice to quit, one other option is to give notice and (if they try to retain you) be willing to agree to a one-year sabbatical, which would allow you more time to feel comfortable about FIREing longer term.
Your health and your family must be your #1 priority.
A question that has often helped me in decision-making is “What’s the worst that could happen?” In your scenario it might play out like this:
Q: What’s the worst that could happen if I quit?
A: The markets tank long term and we can no longer pull enough money out to live on while protecting our financial future.
Q: So, based on the above, what would I do?
A: I’d find another nursing job (always in demand) or some other job to supplement our expenses.
This line of thinking makes it a no-brainer decision to me. You can also take it from the angle of “What’s the worst that can happen if I don’t quit?” I believe you’ll see that scenario has a far worse potential outcome.
Best wishes!