Implantation bleeding or?

Okay, so on the 27th of December I experienced very light pink spotting for just under an hour. Light spotting shown below, that was just the end of the bleeding, there was more than just that.

That was also the day I started ovulating. I have never experienced anything similar to spotting in my life and I have never experienced ovulation spotting. I’m not sure what this could be caused by because I didn’t think I was even fertile. It is now the 4th and my period is due in 10 days.