Miscarriage....I think

I think I had a miscarriage today. I thought it was dry blood because of my period but when I saw it. It looked like fat tissue covered in blood. I wasn't aware I was pregnant. All the test I took were negative. 
Was it a miscarriage? I honestly don't know what it could've been. 
I still cried lol I've been emotional cuz of it but now I know I can get pregnant. I've had too many cases of polycysts in my ovaries to keep my hopes up.