Pregnant after miscarriage?

I miscarried earlier in the month. As of 10/6 my HCG level was at 15 so I assume within a few days after that it was at 0. I have not had a regular period yet. My husband and I were not trying to conceive immediately after, but just are together whenever we feel like it. As of today 10/30 I’ve been cramping (light) and decided to take a pregnancy test. It came back with a faint positive. Could this be a new pregnancy or just still picking up on the previous hormones? I just feel like 24 days after my HCG was at 15, that it would be highly unlikely to have enough of that pregnancies hormones left to pick up on a test but also don’t want to assume this is a new pregnancy.