Light spotting. Awaiting your response.

Hi, am 25 yrs old, married. I was having regular cycle of 30 days. Few months back it colapsed and I was having a cycle of around 39 days. This month I had my periods on 4/1 and my ovulation was around 15 th to 18 th day. on my 25 th day I was spotting and it continues till now,but it's too less to be considered as an early period.I could see that the spotting is not continuous it's on and off spotting without any pain.i could see blood with some dark brown and smtimes even some black kind of discharge. I feel strange seeing this. I had pcod problem 12 yrs back and operated the cyst..from then every year I am going for regular check-up and all records was fine till last check- up. It would be Soo greatful if some one can suggest me on this .I am really worried about this. Awaiting your response. Thanks.