I started spotting lightly 7 days before my period was due. I continued spotting until I started my period-which was 12 days late. Since my period started, it has been extremely heavy with big clots. It has also lasted for 12 days now. I have been prescribed Lysteda for heavy bleeding. I took it for the 5 days, but the period has continued. I'm scared. I had called the Dr when I was 5 days late, and was sent for a blood pregnancy test and that came back negative. What could be causing this. Is a side effect of the Lysteda to bleed like this? I also have been taking Clomid to help me get pregnant.