Miscarriage or just really really big blood clot

I had sex during my fertile window before my period this month, per this app. I took two tests on day 11 of it being late and both came up negative. I started bleeding on late day 22. Today (3 days later) I just wiped a huge blood clot (to me at least as I don't normally see any clots) about the size of a silver dollar coin. Could that be a miscarriage or just a regular ol clot?