Hi ladies!

I have a quick question for you. I am very sad to report that I had a miscarriage at 6.5 weeks that started on May 13th. I stopped bleeding a week later (May 20th), so my dh and I went about our business and wound up having intercourse that following Friday (May 22nd). I received confirmation this past Friday that my hcg was "down" to 3. However, this past Monday (so two days later) I started barely spotting (not enough to even reach my underwear, hardly noticeable on the tp except for two times that I've had a few drops of blood). My dh and I had had intercourse 9 days before I started spotting. Because I have no clue when I ovulated, I'm curious if this could be implantation bleeding? Any thoughts?