6 months post miscarriage... Heavy bleeding?

Nira • Wifey.Mommy.Happy
I miscarried in August 2014, it was early, around 7 weeks.  
I spotted some on and off the end of October and throughout November.. But I didn't Have a period until December 2014.  It wasn't really heavy, I cramped fairly bad, but it ended after about 5 days. 
Now I just got my second period since the mc today, and MY CRAMPS WERE AWFUL. Literally curled up crying and have to take a norco for the pain to stop.  I was bleeding heavily and lost a couple of large peices of tissue (I would say about 3 inches long and the other about 1-2inches) 
The bleeding has slowed already and I'm not cramping as bad (just on a couple midol now)
But could this still be left over from my miscarriage??  I know 100% that I haven't been pregnant since then, but I'm wondering if it's leftover because the cramps were as bad as my mc cramps.   
Anyone experience this, or know what's going on??