Have I had a miscarriage?

I had sex last maybe 5 weeks ago and I’m on birth control (nuvaring). I recently removed the ring and a few days later I began to have cramps and bleeding so I assumed I was on my period as I should be. After two days of bleeding and cramping, I woke up this morning and was changing my tampon. So I removed the applicator. I noticed a quarter sized clot with a string attached. I was a little freaked out but I threw it away and moved on. Two hours later I went to the bathroom again and as I was wiping I noticed this in the toilet paper. So twice this morning I’ve seen a large thick clot like substance. I hadn’t even known if I was pregnant. Is this a miscarriage or just abnormal period symptoms?