Am expecting to ovulate in next three days and did two OPK tests at 3 or 4 in the afternoon over last two days. The test line came up quickly (so test working) but not even the faintest of faint lines appeared. Is this normal? I would expect this at end of cycle or very beginning but around cd 9 or 10??? of a 25 day cycle. I didn't use OPKs latterly when conceiving dd as they were so expensive and didn't really work but want to combine with charting this time to pinpoint ovulation and am now worried that in addition to short LP I have some LH deficiency. Anyone else get blank OPK results and then a few days later strong positive results?