Bleeding all of march so far

Hi all , wondering if this has happened to any of you ? , im 21 , iv got pcos , and my periods are very irregular, I had a 8 day period in the end of February and started again 9 days later , which had now been going on for 25 days so far , it's not overly Heavy like my normal periods , it's really light and quite brown .. not sure of this is just old discoloured blood ? Or if it could be implantation bleeding? Me and my fiancé have had unpretected sex only a few times since .. or could this all just be my pcos playing up ? Anyone had similar? Or have any advice other than go to the doctors ?