Confused please help

So I had a miscarriage last month and decided to ttc right after bleeding since my miscarriage occurred less than 5 weeks along. According to glow I should be 9dpo.

I went in to the Dr's today just for a check up and talk about my options since I have had a history of miscarriages.

The Dr routinely takes a urine sample and tested for pregnancy. Well he informed me it was negative; however, I also got my hcg levels checked 1 last time to ensure it was at 0.

I just got my HCG levels back and they are at 47! I don't understand how my pregnancy test was negative with a result of 47 as my hcg level!

I guess I'm confused and want to know what everyone's opinion on the matter is?

Update: the dr called and asked that I get a repeat hcg test! We will see!

Please be my rainbow 🌈 baby 👶