I started my business in 2000.  For the next ~15 years, I was a solopreneuer.  Fortunately, I made many friendships in the business, and have been able to lean on a few of them for local work when my wife insisted we take actual vacations.  Over time, I also realized that I can only take my business so far alone.  With that realization, I've begun finding people who are better than I am at various aspects of the business--marketing, sales, specific tech specialties, etc).  Since I am a member of Alignable and other like-minded groups, I've found a community of sharing that actually benefits everyone.  I can farm work out to others and share in the profit.  Likewise, they can farm work out to me for shared profit.

Find trusted and talented individuals to help with your workload.  You will likely find they have needs you can supply as well.  Explain to your clients if necessary what's going on.  If sharing information about your medical situation is not advisable--often it is not--say that you are bringing people onboard to maintain your availability, speed, and quality while expanding your capacity.  This is true, understandable, and business-like.  Arrange your personal finances to accommodate the potentially smaller take-home pay you'll experience during this period.

You may find as I am finding, that sharing the workload allows you to take your business to the next level, despite your medical challenges.

All my best wishes for you and yours....