Aih, sabar ye mama, faint line tu memang bikin stress! Dari apa yang you describe, sangat mungkin LH surge kamu detected on CD18 (tu sebab OPK positive), tapi the hCG level mungkin still too early to pick up on UPT even dengan 4 kali testing. CD20 negative tu also normal sebab kalau implantation belum happen or hCG belum rise enough, obviously UPT akan negative pa. I'd say wait a few more days and test again, most mamas dapat clear result by CD24 onwards, tapi honestly, if you're getting anxiety dari testing berulang kali, better to book in with your doctor, they boleh do a blood test which is way more reliable. Fingers crossed for you!