Missed Periods, Taken Meprate Course. When Can I Expect My Periods?

Hello Doctor!! Its been 2 n half months i haven t got my periods. I have taken Meprate tablet for 3 days (2 tabs ech day morng and nite). Can I please know In how many days can I expect the periods??? I have irregular periods always. I have taken many treatments too but its still the same. I have taken the same course of Meprate tabs for 3 days (2tabs ech day) when i did not get my periods last time for around 2 and half month. Do I need to take these tablets every time I dont get my periods?? How do I regularise the periods without taking the tablets. Please suggest. Thanks in Advance.. Awaiting for your reply.