I had no symptoms after the first dose of Moderna vaccine.
After the 2nd dose 4 weeks later, I felt under the weather for one whole day. Body aches, feverish feeling but no measurable fever, and tired all day following the day after inoculation. I was told by more knowledgeable person that means my body recognized the virus intro done by 1st shot, and my body mounted a stronger response to the same protein in vaccine. If body recognizes the invading protein it is because of anti-bodies present. I will burn 81 candles next month.
Well good on you! Your immune system is still functioning as it should. I had the exact same experience with the Pfizer vaccine even though I am “only” 69.