So confused! Please tell me your experiences

I became pregnant in August 2014..only to find out at 12 weeks that there was no heartbeat. I ended up having a D&C the following week. This all happened the beginning of november. I had a normal period the middle of that month. My period was expected to come December 14th but didn't. I've been very emotional, sore breasets, I feel exactly like I did when I was pregnant before. I had light bleeding December 21-23 but nothing like a normal period (mine last 6 days). I've taken several tests all coming up negative. Any opinions?? Or any experiences of something like this after D&C? thanks!!!