Endometriosis. Endometriosis? why so?

I underwent laparoscopy on 28th Oct,16 to diagnose chronic pelvic pain.It revealed that I had endometriotic deposits and a chocolate cyst. As per the doctor, the deposits were removed. My period before surgery was on 7th sept. And after surgery, from the next day itself I started bleeding like period. It continued for 7-8 days. But after that, I didn't get period around 7th of this month. My doctor thinks, I must I have got period early. Is this possible? I have been told to take duphaston tablets from 5th day to 25th day of my periods, which I will be taking when my next period arrives. How effective are these tablets in suppressing endometriosis? Even after surgery, I do get the same pain along with other symptoms like abdominal pain, bloated sensation and discomfort. Why so?Being unmarried currently, I am also worried regarding my fertility in future due to endometriosis. Please suggest.