Miscarriage

I tested positive on multiple home tests about a week and a half ago/2 weeks ago when I was expecting my period. This last Sunday I started spotting and light bleeding, which I never have done with my previous 3 kids. If I were actually pregnant I would’ve only been 4/5 weeks. If this is a miscarriage, how long does it typically take for HCG to get out of your system? I’ve been taking tests every few days still and wondering if and when I should be getting a negative instead of positive