Without discussing medical history, I would contact organizations (schools and employers) that do do medical billing and coding (or for any job change for that matter) to do "information interviewing" to find out exactly what the demands are, even with working from home. Let them know you are interested in changing careers and wanted to know more about the field before making the jump. Most are happy to help.

Find out what the requirements including certification, demands on their time, quotas, advantages, disadvantages, expectations, technology required (as some places provide this, some times you are required to provide it), ask what they wish they had known before going into the field, what do they like and dislike about about what they do, etc.

This should help you to make a better decision based on those that are actually in the field than based on what you think it might be like. I know this made a huge difference for me when I wanted to change careers and started asking questions as my ideas of a position were necessarily in line with what was actually happening in the field.

I wish you the best in whatever you decide. Good luck!!