Everyone is different with the HCG...some people have lower hcg's...I wish you all the best. It is slightly concerning that it didnt double. but please Stay positive.
At 10weeks pregnant I started bleeding, and my hcg was followed for about a week and it was declining. My dr said I was miscarying...I am now 24 weeks preggers and baby is fine.
Between 8-10 weeks hcg can reach is peak and begin to decline after that, but usually stays above 20, 000.