Is Pregnancy Test Advisable For Delayed Periods?

Hello Doctor, My periods were late last month. My doctor gave me folic acid tablets and duphaston to regulate the periods, which I took from 4th Jan (18th day of my period) to 13th Jan. I should get periods within 7 days after stopping this pill. It is 21st Jan today and I still have not got my periods. Should I wait for a few more days or should I consider doing a pregnancy test. plz reply soon. thanks.