Implantation Bleeding??

Alison
My period went from Jan 17-21. I used OPKs this month and should have ovulated either the 4th or 5th. My period isn't due until the 17th of February. Today when I used the restroom I noticed some discharge in my underwear that was creamy cm with some dark brown blood (small amount). That was at about noon and I've had nothing since then. Does that sound like spotting/AF or possible implantation bleeding?? :/ Anxious!!!