Hello doctor, my periods are delayed it's been around a week and still I haven't got my periods back. On 11th to 15th of nov we had protected sex and on 23rd nov I had my periods for 6 days. But after that I haven't got my periods back. My periods generally comes within 33 days but this time it's over 40 days. What should I do? Is their any chance of pregnancy? If not, could you please prescribe me the best medicine for my menses to begin? Please help.