Health problems (which you say you have) don't pop up every Friday, Saturday, and Sunday. I work retail, not my first job. I work almost every Friday and Saturday, and so does the owner. The store is closed Sunday and Monday, so everybody gets a two-day weekend. For most retail, Friday, Saturday and Sunday are the busiest days of the week. If you can't work those days, you aren't needed.
While I do work every Friday and Saturday, (at 62 years old) the boss also paid me my regular wages when my husband died (I was off two weeks) when my mother died (car accident, she lingered a while before passing away, another two weeks), and has told me to stay home with pay for many days this winter when the traveling was hampered by snow storms.
Although he owns the business, he comes into work five days a week. He's in his seventies.
If you want the weekends off, find some kind of business that isn't open weekends. That used to be banking, but now even a couple banks are open seven days a week. My furnace repairman works six or seven days a week in the winter, (was here on Superbowl Sunday, but planned to be finished by 6 p.m.)