Are you taking it at the same time everyday? Also, sometimes if you take your pills at a different time than the last month it can throw off your period. For instance if you took your pills at noon, but then the next month you started taking them at 5 it would throw your period off by a couple hours. However if you're taking them at the same time everyday and every pack is the same time, then that shouldn't be happening. Or your body might still be adjusting to them. If it starts to get days off I would see your doctor.