I started taking the birth control pill Seasonique, it is supposed to give you 4 periods a year. My first 3-month dose was going good, and I am not supposed to get my period until the 13th week. I got my period on the 9th week and I am still on it, it is now a few days before the 12th week begins. Before I started on the pill I would get my period every month for 3-4 days at the most. The 13th week of the pills have a lower estrogen level, which will cause my period again. Should I be concerned? I have taken several pregnancy tests before, during and after I started with this pill, and they are all negative.