Please help maybe miscarriage

I ovulated 2 weeks ago I had a lot of brown blood for a few days which I learned was normal. I’m supposed to get my period in a week however the last 3 days Ive experienced numerous amount of dark brown tissue and blood when I wipe. When ever I pee their is clumps of blood floating in the toilet or on the tissue paper. I’m supposed to get AF next week. I’ve never experienced anything like this. I took a PT yesterday and it was negative, could I be experiencing a miscarriage? This is not enough blood for my cycle. This is very abnormal.

Has anyone experienced something like this?