Graphic post, was this an early miscarriage?

Hi all, last week I had bad lower back pain all Wednesday evening and Thursday morning, but I was on my period and it was a particularly heavy one. I was walking round the house and felt something pass, but I thought it was just a blood clot.

I went to the toilet and saw regular period blood, and then something which was completely separate and autonomous to the blood. It was the size of 1.5 x bigger than a £2 coin, and it was a sac which was bigger at the top and longer and thinner at the bottom. It was filled with blood clots and it was grey and fleshy. When it disintegrated, it looked like the photo below. Was this an early miscarriage?