I do not have the time to get sick. In almost 4 years of being self employed I was never sick enough to warrant a stop in my manic schedule.
Last year I delivered and set up a cupcake wedding cake with a sprained ankle. I missed a step in my shop just an hour before and after sucessfully fighting the dizziness I limped to my car and delivered the cake.
So you get tough and get on
But of course there should be a back-up plan. My mother would be able to cover the more basic stuff and my sister can run the storefront for a day or two and I have a part-time help who can bake and run the store as well. As mentioned previously, the cakes and relevant preparations are scheduled over the whole week so I can also catch up if I'm out for a day.
My first full-time employee will start in July so I'll be covered for almost good ;-)