HCG after miscarriage

Sarah • ⚓️Navy wife. Rainbow baby 🌈 👶🏻May2019..ttc baby #2

Have put in a call to my doctor but waiting on a response and figured I would see if anyone had a similar situation in the past.

I had a miscarriage (blighted ovum) in January we found out at 11wks. Had a D&C; done at 12 weeks Jan 28th.

Had been monitoring my HCG levels with my doctor and three weeks ago she said they were at 40 and should be at 0 soon.

27 days after the procedure I got my period, only lasted 4 days opposed to the normal 5.

When it ended this morning I took an OPK test and pregnancy test just to know I was starting at negative but it is still positive.

Has anyone ever had this happen before? That you got your period after miscarriage but still had HCG in your system?

Thanks for any advice