I had unprotected sex when I was taking the pill for the first month, had taken for 2 weeks, my period came 13 days later. then my period came again early, only 3 weeks after my first period on the pill, then it came back again when it should have come, on the placebo pills, it was a vivid red and thin blood, and I took a pregnancy test 10 days after the sex and it was negative, and like one month after I took another test and it was negative, but its possible for.me to be pregnant? the most strange thing that made me nervous was the last period, the vivid thin blood..