BC Pill

I started taking the BC pill a couple of months ago, but stopped right after the second pack because of the bad headaches. Made an appointment to get the IUD right away, but my doc was booked out until the end of Oct. My boyfriend and I had unprotected sex 3 weeks after I stopped taking the pill, but I started back taking it that following Sunday after we had sex. Now two weeks later after taking the BC pill religiously, my period is 5 Days late. Could it be the BC pill stopping my period? I went to the doc last week (which was a little over a week after having unprotected sex) and took a test, that came back negative, but she said it might be too early to tell. I’m so stressed out about this. Can someone give me a little clarity.