Hi, I Use To Have Regular Periods Exactly On 31st

Hi, I use to have regular periods exactly on 31st day but in august due to heavy work and i visited tirumala immediately i got date(21st day of my cycle) i consulted doctor and the doctor told its not a prblm and it is regular again but last month i got 1day before(17th sept) and this month i didnot get my period yet and i had engagement function on 27th of this month so i used 2 tablets of regestrone on 18th to get it early but i did not get, and next month 23rd its my marriage date what to do now? Can you please help me