Why am I bleeding around ovulation?

So I went to the bathroom and noticed that I was bleeding. I’m not even close to starting my period, its around my ovulation period. About a week ago I took Plan B so I am unsure if it is the pill or could I be pregnant? I took the pill about 12 hours after I had sex. I have also taken Plan B before just to be safe and it never caused me to bleed. This has never happened to me before so does anyone have any advice?