What Causes Vaginal Spotting Before Periods And Followed By Heavy Periods?

Hi I am 34 year old. 153 cms,44kg.Two years back I used to have hevay bleeding during my periods 7 after consulting doctor & after scanning she said tehre is a cyst in my right overy. I took the treatment(registrone) & it was cured. BUt bleeding was still heavy after that. Now, since last 1 year everytime before my periods I get spotting for 2-3 days. Then after that for 2 days there will be no bleeding & spotting. on 4th day the bleeding starts & it will be very heavy for two days. then it reduces gradually & stops on 6th or 7th day and sometimes on 9th day. And in his month I am got spotting on 13 thday of my periods. Also getting a very little blood after having intercourse. Could you please let me know what must be the problem