I have been taking birth control pills consistently for 6 months. They brand causes my period to come sooner on the 23rd day of the pack. According to my calculations, this causes my ovulation to occur during the placebo pills (i.e. First date of period was March 28th, ovulation to occur today, April 10th). I had intercourse yesterday, Am I at risk for pregnancy? Also, I am taking tegretol for seizures, which lowers the effectiveness of the birth control. Do I need to get the morning after pill? Thanks for your help!