Frustrating HCG

Has anyone else had issues with their hcg not dropping after a natural miscarriage? When I first began bleeding my hcg dropped from 2300 to 600. They also did an ultrasound and the dr said it looked like I had passed everything. They wanted me to come back 2 weeks later for another blood test to make sure my levels continue dropping. Well I got my results today and the hcg stayed the same and hasn't dropped. Does anyone have any experiences like this? I'm going in tomorrow for another blood test but I'm terrified I didn't pass everything and will have to have a d&c😒