Blood clots in your period?

I was around 3/4 Days late for my period, it started off different than usual also. The day I finally put a tampon in due to heavy flow, when I removed it, it looked like a long thick blood clot attached. Could this have possibly been a very early undetectable miscarriage? Or is it something that just happens to you women as well? I’d love some input, thank you in advance! P.s. this does not happen normally with my cycles. It’s happened maybe twice before.