I had sex with my boyfriend on April 17th (the day after my period had ended) . We won't have sex unless we had a condom but this time the condom broke and we weren't sure if he got out in time. Within the hour I took an emergency contraceptive. My period was supposed to come on the 6th of May and it's now the 17th. I've also had four pregnancy tests using First Response and they all came out negative. I am also moving into an apartment later this week, I started a new job, and there's a lot of family problems going on. Could I be pregnant? Is my period delayed because of the EC or because I'm stressed or maybe both? Any suggestions are greatly appreciated.