I had a similar situation due to injuries and had to leave the field after 20 years. It was hard. Still is.
I'm not sure how valid it is to generalize, but here goes: Maybe start with a list of all the stuff you like to do -- not trivial things, like watching a particular TV show, but ongoing activities. Delete items that have no income-earning potential -- e.g., eating grapes. Don't be too hasty to rule-out possibilities -- lots of small businesses begin as hobbies -- but most of the items on the list likely would require someone else to pay you to do them. Be honest with yourself about your education and experience in those areas.
Most of the things on my list got crossed out pretty quickly. For example, I would have liked to be a musician. All I lacked is talent. Or playing competitive hockey again -- pretty hard to do when you're 66 with a bad back.
I ended up focusing on two areas: merchandising and writing. Those fit because I had experience developing products as an engineer, and started as a sportswriter many years ago. Writing turned out to be a good choice; it's helped pay the bills. Merchandising? Not so much, although if you combine the two products I introduced, I made a profit. I also learned a lot, which might come in handy again. I'm not going to say, though, that either has been as much fun as 9-1-1 was.
If you have money in the bank and can go back to school, that creates more possibilities. It also helps if you're young and healthy.
Can you partner with someone in a similar situation -- someone with similar interests and a compatible personality? That might be an advantage.
Is your family behind you? Are there choices that work better for them, if not for you?
If you don't mind a brief editorial, I'll end by saying that this is a great example of how college degrees can help. The opportunities they create don't necessarily have anything to do with EMS. Too often, people in our industry limit their views on that topic to the jobs they're in right now, rather than where they might want to be a year or 5 years or 10 years from now. Often, we can't predict that stuff.