6 DPO Light Brown Spotting and 1 Dark Brown Blood Clot

Has anyone experienced this with implantation or know what it can be caused from? I am pretty sure I had a chemical pregnancy last month. That being said, I track my ovulation using opk’s so I know exactly when I ovulated, and I am not due for AF for another 8 days. Starting 5 DPO, I started spotting, but past this one clot (TMI) at 5 DPO night. 6 DPO now, and barely any spotting only a tiny bit of light brown when I wipe. Also should note this has been accompanied by consistent dull cramping and lower back ache. HELP! (These pictures are in sequential order leading up to today).