hi, i have a question regarding a possible pregnancy. my last menstrual period was on June 3, 2015. i had unprotected sex on June 4, 2015 (my regular heavy flow), but the following day my period stopped (June 5, 2015). i took an emergency contraceptive pill on June 6th along w my BCP, which I have been taking regularly for the past 4 years. however, I started taking antibiotics for a UTI on June 7th and i have concern that it may have cancelled out the emergency contraception. i took a pregnancy test on June 14th and today, both of which were negative. is there any possibility that i could be pregnant with these factors in mind?