Endometriosis, Spotting since 1 month.

I am an endometriosis patient under treatment of IVF, egg retrieval done but transfer will be done after some months. For endometriosis Dr prescribed me to have Tablet Visanne from the month of February. In every 30 40 day I have spotting for 20 days around. When spotting starts I skip Tab Visanne for 2 to 3 days after 6 to 7 days spotting stops but this time spotting started from 18th August and it's continue till today (sometime itchy or burn). I skipped the Tablet for 2 days but it doesn't work. I have told my Dr he said continue the Tablet Visanne inform if there is full bleeding. As I am in abroad now. Dear Doctors ! what is your advice and suggestions? Is it matter of concern or it is normal to have prolong spotting in endometriosis?