What Should I Do If My Period Hasn T Come After Completing One Batch Of Novelon?

Hello dr.Last month I have my periods on 25th March..after that acc to dr.presciption I have started taking novelon from the day 5 of periods...I have completed one batch of 21 pills...after 6th day still my periods has not come.. what should I do now ? And again when should I start taking the 2nd batch of the novelon 21 days pill ?