I got started because I couldn't get another job, taught myself to code and one of my ideas that I was working on learning to code turned into a biz.
From there, I've had multiple projects, I don't like calling them businesses until they are. It's just a project I work on on the side.
You say due to health reasons you can't put in extra hours on the side, I'd say focus on your health as #1.
Would your employer give you 20% time to work on a side project? Would that work for you?