Hi, My Last Period Was On 2nd Nov And I

Hi, my last period was on 2nd Nov and I was expecting my periods on 1st Dec... But till now (21 Dec) my periods not yet started..I did Two pregnancy test and both were negative..I consult with my gyn, she prescribed me Registrone 5mg for 3 day three times in a day.. Is there any chance to get pregnant??? Or by this I get my periods..?Plz help