Blood clot or miscarriage? TMI

I’ve been on what I thought was my period for a week, this morning I woke up from awful low back pain, then the cramps started around 10am and were 9/10 pain for about 2hrs then stopped. About 5pm I changed my tampon and felt a large clot fall out. It accidentally got flushed ( automatic toilet) then I felt a second one coming and caught it. It was squishy but firm.