... 2 years and it worked great. I always got my period consistently on the 4th Tuesday of the pack. I started getting auras and told my doctor and they thought it might be because of a hormone imbalance caused by my birth control. I got switched to errin and took the pills for a month. The first week, I was in pain like I was on my period and experienced no bleeding. Finally the 4th Tuesday came around and my period didn't show up. My boyfriend and I had had sex while on errin and I did take the pills consistently, but no period. It has been almost a week since I expected my period and still no signs it is even on its way. I have gone back to my old birth control meds. I talked to my doctor, she said I will probably miss a period and then catch up on the 4th Tuesday of this pack of my old birth control pills, but my boyfriend seems concerned knowing how consistent my period was. Am I pregnant? Did the pills not work? Am I due for my period probably on the old birth control at the end of the month?