I am a "Perfect" Birth Control user. I have never missed and take it at 10am every day. This month I had a UTI and was on the antibiotic Microbid for 4 days, I still took my BC everyday. About 5 days after I had been off the antibiotic my husband and I had sex for the first time since before I started the antibiotic, he put it inside me fore maybe 20 seconds before I said I wanted to use protection because I had taken antibiotics 5 days prior (he did not ejaculate). I was nervous about pregnancy, so about 24 hours after the sex I took Plan B and we haven't had sex since (It's been about 7 days). The issue is that I'm on a type of BC that makes me not have a period, I haven't had one in almost 2 years. Today was the day on my pack that I should start my period and I have some light red and brown spotting ans slight cramps. I know taking plan B can make you have your period, but I just haven't had one in so long. Could this be signs of pregnancy?