Period after getting vaccine

I had been hearing that the vaccine affects our first period and some people have it really bad. I got my Pfizer vaccine about a week ago and yesterday I got my period. I started with my usual cramps and I took acetaminophen but they just subsided, never really went away. Then I woke up at 3am in so much pain and couldn’t sleep so I took pills again. This morning I touched my pants and I was drenched in blood. I went to the bathroom and the entire front part of my underwear and shorts were drenched in blood. Should I be concerned about this? Or is it normal?