I am in quite a stressful situation. I take birth control, orthotricyclen, for the past 2 years. I was put on a z-pac at the beginning of the month and finished soon after and I continued to take my bc normally. On Friday I had unprotected sex. About a half hour later I took the plan b pill. It is now Thursday and my period was due Wednesday. I have never been late especially since I'm on birth control. I am now worried I'm pregnant.