About a little less than 3 weeks ago, I had sex and the condom broke but we couldn't tell at the time and he came inside me. I took plan B the next day. My period was supposed to come on the full moon (a week ago) but it hasn't yet and while it was supposed to come I was getting random cramps and my breasts were swollen and really painful. I took a pregnancy test a few days ago that was negitive, but it could be too early to tell? I haven't gotten any spotting and I'm really terrified to take another pregnancy test. But could plan b still be causing all of this?