[Kate*]

I had Pfizer also. My arm was super sore after the first one because of the way he did it (lasted about 4 days) and I got a headache after a few hours, but I get those all the time, so it may not have been related, and then my arm got swollen and red again on day 8, around the time I ovulated. Apparently, hormones increase your immune response?! The second one was bad enough that I called off work the next day, but not the worst I've ever felt. Just tired and achy.

If I had to guess, it was probably a coincidence. You caught something and weren't symptomatic until after the vaccine, which if that happens, can give you a worse reaction, and then that could've triggered your period, and whatever it is has now become possibly a sinus infection, so you might want to get it checked out. But, I don't think it was directly related to the vaccine, at least not entirely.