Ovulation spotting?

Quick backstory. On June 3rd, I had a d&e at 21w3d because my baby had a neural tube defect. I got my period back 5 weeks later. On cycle day 10, I noticed that I had a little bit of reddish spotting right before my fertile window started. I had spotting again on cycle day 12 and then yesterday on cycle day 15, I've started this brown spotting. I've been tracking my ovulation through opk's and I haven't gotten a high or peak result yet. Has anyone else ever spotted during ovulation? (We want to try and conceive again and are having unprotected sex).