high hcg after 6 weeks of miscarriage?

Katie
Has anyone else experienced this problem? I went in for my 12 week ultrasound appointment and we found out that we lost the baby around 8 weeks. My body had no signs of miscarriage and so I had to take medicine to pass everything. 3 weeks later from the medicine and 6 weeks from when baby passed or so the doctor thinks I still have an hcg level of 40,000 and still showing a positive pregnancy test result. At the 12 weeks appointment my hcg level was at 123,000. Please tell me somebody else had this happen?