Positive test after miscarriage

G

Y’all I am very late for my period, I had a miscarriage early/mid December.

And it’s ALWAYS on time or early.

I took a test and it’s obviously positive. But how do I know this isn’t left over HCG from my last pregnancy?

I don’t want to get my hopes all twisted in this

My last HCG was 4000/5000 about 4 weeks ago & I have no remaining tissue