Miscarriage after negative test?

I took a pregnancy test on Friday. It was negative. I took it because I was 9 days late on my period with milky discharge and my nipples were really sensitive (which never happens). Saturday evening I passed a clot about the size of a quarter. I assumed it was my period. Now I’m almost 4 days in and the clotting has gotten bigger and worse along with the bleeding and abdominal pain and back pain. This doesn’t feel like a normal period for me. It’s worse. I’m going to the doctor in the morning. Has anyone ever had this happen before? I’ve never been pregnant and was recently diagnosed with PCOS and I’m HPV+. My gut is telling me I’m miscarrying, but have no proof because of negative test. In the past my periods have been very irregular, but in the last 6 months after losing 30lbs they have been regular. I’ve never experienced a period this bad before.

Edit to add:

The doctor confirmed I am miscarrying.