I Had A D&C Done Last Year Because Of Heavy

I had a D&C done last year because of heavy bleeding, large blood clots (4 or more in one day), and was having periods that were lasting two weeks or more. My periods were getting better there for awhile after my D&C. However, my periods are back to lasting longer and I only had a week and half between my last two cycles. My last Cycle started last week Wed and I still have my period. What could be causing this? I am 44 years old.