Period or miscarriage?

I was late of my period for two weeks,

I had unprotected sex on 08.03. Than 14.03 i had some spotting. I thought it was implementation spotting. After missing my period i did test few times and it was all negative. I did ultrasound after 8 days of missing period and there was nothing.

Doctor said that lining was so thick that there was possibility of pregnancy which wasn’t visible on ultrasound yet. 3 days ago i did pregnancy test again and second line was very very light.

Yesterday I started bleeding, I thought I started period but it was heavier than usual and i had huge blood clots. More painful cramps than i used to have. And color of bleeding was very dark, almost brown.

Did i miscarriage or it’s just period.