Is this a miscarriage?

Graphic image, I posted this in another group but looking for answers from anyone that has experienced this! Yesterday I started experiencing all the normal period signs which considering my calendar it was right on track, but no blood. Later in the night I had a dark brown/red discharge but no bleeding. Woke up this morning to more cramping and blood so I thought okay I just started a day later, no biggie. Light bleeding throughout the day just like a period until a few hours ago I had some heavy cramping come back (usually cramps are heavy the first day for a few hours then goes away). I felt an extremely large blood clot, went to the bathroom and found the largest I have ever passed with what appears to be grey tissue. Did I just have a miscarriage? I wasn’t aware I was even pregnant. Help!