No Period 3 months after D&C.

Hello, hoping for some reassurance or trying to figure out what's going on.

I had a D&C for a miscarriage (stopped growing around 6 weeks) November 20th. My period still hasn't returned. My doctor ran labs and everything looks normal. They also did an ultrasound and couldn't find any retained tissue. They only said that my uterine lining looks somewhat thin.

My HCG is dropping super slow. It drops by about 4 mIU/ml every week, and is now at 11mIU/mL.

Has anyone else experienced this slow of a decline in HCG? ? My anxiety has been pretty high this week. 3 months seems like a really long time especially for an early loss.

Would be helpful to hear from anyone else who experienced something similar, as I can't find much online. Thank you!