Wa'alaikumassalam sis, I feel you, detecting ovulation mmg tricky sometimes, OPK ikut cycle je so boleh jadi beza beza timing. Honestly, ramai moms yang tak detect properly tapi still dapat pregnant sebab timing memang tak kena point, sometimes intercourse yang regular je (every 2-3 hari throughout the month) lagi effective daripada tunggu OPK positive. Couple of things: make sure you're doing OPK at the same time setiap hari (biasanya afternoon/evening lebih reliable), check your cervical mucus jugak (stretchy clear mucus = fertile window), dan jangan over-stress about pinpointing it exactly, stress lagi jadi kontra-produktif. Semoga rezeki Sya cepat dapat tu! Tapi kalau after a few months still susah nak detect atau tak dapat juga, takpe check with your doctor okay, boleh dia guide you better.