Miscarriage HCG

How long after your miscarriage did your HCG drop to below 5??

I miscarried July 16 and had my blood taken 4 weeks ago and HCG was 113 and 2.5 weeks ago and my HCG was 50. Took a test today out of curiosity as I’m approaching first ovulation week and there’s a noticeable second line still (lighter than when I tested 2.5 weeks ago but still not even a squinter! Ahhh so frustrated 😰)