Clot or Miscarriage???

Diane

*Reader discretion: TMI

2 days into my period, I had THE WORST pain I've ever felt in my life. I could barely crawl to the bathroom, and I passed something about the size of an avocado, and I swear it looked like a fetus. I didn't take a pic, but I showed hubby and he agreed. I went to the Dr. but blood test was negative and doc said it was a blood clot bc I use tampons which makes the blood pool. I change my tampons out tho, and I have no history of clotting or heavy bleeding. Could doc be wrong? Or is there something idk?