Should I be worried?

The last time I had sex was October 6th with my now ex boyfriend. I was on the pill when we had sex but he did not wear a condom that day. He did pull out and I felt fine. I had a period both in October and November but it’s December and I bled for one day and it stopped. I’m still taking the pill and I haven’t been sexually active since him. Part of me feels like I’m overthinking and I’m fine but part of me is still very scared. I asked a friend and she told me when she started the pill her period was still irregular then it stopped and now she doesn’t have one and I shouldn’t worry, my period is probably stopping slowly. So idk if I should worry or not.