Sudden spotting 15 days after miscarriage. What gives?

I miscarried 15 days ago, bled for 5 days, and finally got a negative pregnancy test on cd 9. So we’ve been excited to get back into the groove and try again. I’m tracking everything (cm, bbt, cp, opks) and while I haven’t had any fertile signs yet obviously I felt like things were mellowing out and we might be getting there soon.

Suddenly today while checking cm it was creamy brown and then reddish brown like I’m about to start spotting. What the heck could be the reason for that?? I’m so frustrated and I just want things to get back to some kind of normal so we can try again.

Has anyone else experienced random spotting 10 days or so after the bleeding from the miscarriage stopped?