My husband and I have been ttc for almost two years. I've been taking OPK tests since Sunday and I'm currently CD 15. My cycles are usually about 24-25 days long. This is the most recent test and the line still doesn't appear as/darker than the test line. I'm confused because originally all 3 apps I use said the best day to BD was Monday, now they're all saying Wednesday or Thursday of this week. Is it possible that I skip ovulating for a cycle or is this a positive test?