Any advice on swapping to a new career?

Hello all, first time poster. I'm in a tough spot trying to find a somewhat fulfilling job and would welcome any advice on how to move forward.

I'm a 34 y.o. male in the southern US. I graduated HS but no higher education. After a medical separation from the navy in 2012, I started working in construction. I moved up from a laborer to a grade finish operator with almost any piece of equipment you can imagine, then became a certified crane operator, while working in petrochemical plants.

About 3 years ago, my health began deteriorating and I could no longer perform the work, so I had to back out of my career. I had to move back in with my mother, and have been working odd jobs since, currently as a janitor at a home for the mentally deficient.

All of my previous certifications are expired (NCCCO, OSHA 40, TWIC, security passport, etc) and I am a medical cannabis patient, barring me from the construction or transportation sectors.

I'm a quick learner, but having too many interests has made it difficult for me to pinpoint anything in particular that I would like to push myself towards. My interests include engineering, law, biology, compliance, and just solving problems in general. What would be some decent options to try to get in to to be able to afford healthcare and a decent living?