BC does not match cycle

I’ve been on the pill since April 2020 and have not missed a pill. I’ve noticed that some months my period starts early and throws off my whole pill pack.

I just finished my first week of a new pill pack. Which would mean I had my period 2 weeks ago. But instead I had it 3 weeks ago (meaning I took the week of sugar pills after my period, and took active pills during my period). So now I am completely off by a week. Is this normal?