To the original poster: we had a similar situation on a cruise in January 2023.
Even though I wore a mask the entire cruise, I started to feel sick and had a fever towards the end of the cruise. I had brought some Covid tests with me in my carry on since I had read that this is the safest way to carry the tests. I took a Covid test and it immediately showed positive. I called the Medical Center, and the nurse I spoke to was very nice, but he said those tests tend to show false positives and Covid is not that bad anymore. He said I could come down but only if I wanted to. I did go down the the Medical Center where they took my vitals and the nurse gave me another test which looked exactly like my home test. He barely swabbed my nose and showed me the negative result much earlier than the 15 minute wait time. He said that they could do further testing or I could see the doctor.
I decided that I had done my duty reporting my illness, and if they were not concerned, I should not be concerned. My husband became sick the next day. Fortunately, we had two sea days and we skipped one of the ports. We both wore masks and ordered room service for a couple days until the fever broke. We continued to wear the masks the rest of the trip, at the airport, and on the plane.
It was not too bad being sick on a cruise. We were able to get room service with chicken soup. We sat out on the balcony. Fortunately, I had brought a lot of over the counter medication and neither one of us was that sick.
I was very disappointed in NCL's response. I thought they should have taken me much more seriously.