Does Taking Medicines To Postpone Periods Cause Irregular Bleeding?

Hi Dr. My problem is recently I underwent surgery (Vaginaplasty-expansion of my vagina) and post surgery, I was dilating for a month, during which time, I took tablets for postponement of my periods. After the discontinuation of the tablets, I had my periods, the first day was very painful, second day did not bleed for whole day but started in the night....and on the sixth day until this day, there has been Reddish brown watery fluid flowing. Do not know, what the problem is??? Please let me know, thanks