I'm on the birth control method of patches and last Monday was my change date (the last patch of the month before my off week). But it was also the day before I was supposed to start my period. I've never had unprotected sex. We always use condoms and I'm on birth control. The last time we had sex was at the beginning of the month (September). Now that it is my off week when I'm supposed to get my period it has yet to come. It's been over a week it was supposed to come too. Is there any chance of pregnancy or maybe my patches hormones could have thrown it off??