it vary by person tbh. i had no side effects after both shots of Pfizer but it just gets super sleepy on the day of 2nd dose. while my sister was down with high fever for 3 days after completing her doses

It varies from person to person but I'll tell you my experience, maybe someone here had it similarly.

The first shot was nothing but a sore arm. I got the second shot during the night time and was fine for the rest of the night but the next day, I had a headache during work but took Advil. I was feeling light headed after work so I took another Advil and took a nap. Seemed like I had a fever because I was sweating and was chilly. Took me a couple hours to fall back to sleep and the next day I was fine.