positive pregnancy test after miscarriage...

Mary • mother of a beautiful 15 y/o & 2 angel babies 👼 5.04.18 / 🌈 09.19.18 💖

how long after a miscarriage does a pregnancy test stop detecting hcg? had a miscarriage on 5.04.18, stopped bleeding 5.09.18 & had intercourse 5.14.18 & 5.19.18. I've been taking hpt to see if hcg has gone down. is it me or does the one from today seem darker than the one from the 19th?? is it possible it could be a new pregnancy or is it still detecting from mc? or is it still too soon to detect a new pregnancy?? I'm confused! 😕😞