I had my last period on 13th Feb. We are trying for a baby. In March month periods did not happen. It happened on 04/04/2018 but only at night time and was clear on day time. We did urine pregnancy test but it was negative. We consulted gynecologist who prescribed us undernoted medicines 1) Decdan 0.5 mg 2) letrozole tablets usp. 3) Beefol tablet. Kindly, advise are these medicines okay and for what reason. I am also experiencing back pain. Kindly advise why is it happening. Is there any complication in achieving pregnancy?