Having the two Pfizer shots previously, my immune response was backwards compared to others. After the first shot I felt very lethargic for a day. Then I was fine. The second shot had no side effects except for a sore arm.
For me it was like Joe. 1st dose (Pfizer) left me tired, sore arm, second dose was no big deal. I think it was because I knew what to expect. Just give yourself extra time to sleep; Nothing to it