I've had unprotected sex about once a week since the beginning of November. The first time I had taken plan B the next day. I got my period the second Friday in November and it ended the Friday after....yesterday I noticed a little blood after I went to the bathroom and it was like blood mixed with like water on the toilet paper so it was a pale pink color...and it's the same way today it's never happened to me before....is it cause I'm starting my period or could I be pregnant? This didn't happened during my period in November so I don't think it's from taking plan B or anything...also for the past week I've been sick with a stomach bug and was badly dehydrated. Is it possible it's cause of that?