What’s going on?

Okay so I’ve been trying to get pregnant, I had my period October 30th-November 2nd. My ovulation day is supposedly on the 13th. My boyfriend and I had sex yesterday and the day before, on days my calendar said I had medium chances and one day high chances. Today it looks like I started my period again? There’s such little blood tho and it’s kind of light in color. I took a pregnancy test 2 days ago and it was negative. I’m not sure what’s going on? Could it be implantation bleeding? This is a picture of the blood…any advice?