Can dropping HCG levels at 9 weeks be normal?

Patient: Are dropping HCG levels at 9 weeks pregnant a bad sign? I am current 9 weeks 3 days pregnant. At 8 weeks 2 days I had blood work showing my progesterone was low (10) and was put in oral supplements. My HCG levels were 61930. I had an ultrasound at 8 weeks 4 days. Baby was measuring right in time with a heartrate of 177. I went back at 9 weeks 1 day for more blood work to check my progesterone. My levels are now 16.5, however my HCG levels are 46398. I don’t have another ultrasound scheduled until 12 weeks and I am so worried this means something bad.

Symptoms: No bleeding or cramping.