I had sexual intercourse about over a month back. We used a condom. Despite that, I took an ipill the next evening. I felt dizziness and nausea for a couple of days. Then got well eventually. I got my period about 10 days before the expected date. It went on normally. I still got unusual headaches and so we decided to take a pregnancy test at home. It was negative. So we figured everything was okay. But since yesterday, there's very light bleeding and still it's not even close to my period date. What should we do?