I had brown spotting yesterday and took the first opk below last night at 6. Still the tiniest bit of spotting when I wipe today. I took an opk at 10 am thinking surely it would be positive and it's barely there. What is happening? Are opks more positive at night? Usually time of day hasn't affected mine. Did I miss my surge? I'm not sure when I typically ovulate. Used to be around 15 or 16, but I've had miscarriages that have caused it to be later the last two months.