Getting a job?

So it has been almost a year since I was diagnosed with Dilated Cardiomyopathy.  I have had my ups and downs.  Making some lifestyle changes takes some getting used to.  Now that all three of my kids will officially be in school for most the day, I am considering getting a job.  I have not had a job since my oldest was born 8 years ago.  All I have done is childcare.  I used to be a preschool teacher.  I do not know if that is the field that I want to go back into or not.  I would like to but I would like to know that I can do more than just be around kids.  Now that I have a heart condition, I also have to take that into consideration when picking a job.  I'm gonna have to get a job that will let me take some breaks so I don't get exhausted quickly.  A job that will let me have light tasks so I don't overdo myself.  I also have to make the decision to tell the boss or not that I have this condition.  I could also go back to school.  Get a degree in something and get a job that way.  There is just so much to think about.