Cramping when skipping period

So I started the pill two weeks ago, but I started it on a day that I wasn’t on my period. I thought I was but turns out I was just bleeding from the Plan B I took a week before, so when it came time for my actual period to come I kept taking the pill because I didn’t want to mess everything up, so I basically skipped my period, but I’m still getting really strong cramps. It comes and goes, but it’s still there and it’s painful. Is that normal?