How long until you get a negative pregnancy test?

I began bleeding 16 days ago, my HCG levels went from 331, 545, 591 in a matter of 6 days. A week went by and it dropped to 335. That was last Monday. I took a pregnancy test today and it still shows that I'm pregnant. I was barely 4 weeks when I started miscarrying. How long will the bleeding last, and when will I hopefully get a negative pregnancy test? I went to my OB last Monday and his words were "you're just going to have to get over it" and he refused to answer any of my questions. :( so I'm just really confused?? :(