Could this be a miscarriage?

Could this be a miscarriage or just normal heavy period? I was bleeding lightly for two weeks then all of the sudden in the night I woke up to cramping and blood clots pushing out of me along with heavy bleeding. The clots were long, black, and firm. I should mention that I’m still breastfeeding my 9 month old, but my periods came back in March. We had sex April first but I thought I had a normal period in between that and this abnormal bleeding. I called my doctor and she didn’t give a shit basically lol