What are the chances?

On CD 29 (Saturday) I began spotting pink. Since my period was due Sunday I chalked it up to being AF.

My period is always 3 days on medium flow with slight cramping, back ache and headaches. With day 2 being very painful and requiring ibprophen.

Well today is day 7 of light bleeding and no cramping, only day 2-3 had been enough to fill a pad (just 1 per day). The last 2 days it has been brown.

I just ordered a pregnancy test for tomorrow morning but my opk this morning was blank (negative). Is there any chance I am finally pregnant or is it more than likely just a weird period?