No apologies needed. Sometimes it is difficult to know the intent just based on words typed in a box. It happens all the time.
It is likely that nobody will ask to see any documentation. But there is always that "if" factor to be wary of. I'd rather carry some letters along that never got opened than not have them and then have someone ask. It isn't usually the cruise line people who ask. For a typical cruise you check in with the cruise line and private port security officers being "the authorities". But it is absolute that when you leave a cruise you will present yourself and your luggage to a U.S. Customs And Border Protection Officer. Some don't smile much. Such is the times.
For perspective, most of the staff here is either your age, close to it, or older. I think most of us have health issues and can certainly understand your situation.
So lets move on from this little misunderstanding!