spotting a week before cycle

Angela

So, I've been on metformin and spironolactine since September. this month I had sex ovulation day and the couple days after. (last week). It's now a week later, 6 days before my period is supposed to start, and I'm spotting. I have never spotted before in my life. I'm wondering if this could be a sign of possible implantation bleeding?

Edit- I'm also experiencing frequent and very urgent urination which is also abnormal for me.