HCG out of system?

Hi! Sorry I'm posting anonymous but I have family on here I don't want to tell yet...I had an <a href="https://glowing.com/glow-fertility-program">IUI</a> on January 25 & 26. HCG trigger was on the 25th.
Today would be 13 dpo, and in the afternoon I took a pregnancy test that was very clearly positive. 
I was wondering if it could be the HCG in my system or is it my BFP???
I have my blood test tomorrow but I'm going to be thinking about it all night!!