How long does hCG stay in your system?

Sharee • Loving life with my sweet rainbow baby! 💗Amelia Nicole💗
Today makes exactly one month since I found out my baby stopped growing. The baby was measuring 6 weeks but I didn't find that out until my ultrasound at 10 weeks and I had a D&C done the next day. My doctor told me everything went fine and that we could try again after 2 weeks of pelvic rest. I bled for about 3 days then just spotted. Then I had period like cramps but I only had light brown discharge (sorry TMI) for about a week. So I'm not sure if I could say that was my period or not 😕
 When I found out I was pregnant the "pregnant" line on the test was so dark it actually pulled dye from the control line. 
Well this morning I took another test because it's driving me crazy not knowing what my levels are doing...and it's still this positive. Is it possible for levels to still be that high after a month?