Hi, thanks for using healthcare magic
I am sorry for your loss.
The rise in HCG
can indicate the retention of products of conception. To determine whether this is the case , your doctor may suggest a repeat ultrasound
and may suggest a D and C based on the results.
The level that you quoted is normally not seen till approximately 6 weeks of pregnancy
and are unlikely to be due to another pregnancy.
I hope this helps and wish you the best