What Causes Bleeding, Spotting And Then Nausea During A Miscarriage?

I start bleeding last sunday march 15 2015 went to er dr told me I was havinga miscarrige..bleed for 5 days total no cramp no pain with clot and some tissued I guess. The 6th day no bleeding no spotting alk they til around 6pm i did a pregnancy test was positive start feeling pressure and spotting again..feel super nauseated whats its going on? Am I still pregnant?