O is low, u will have to track for 2 months, u will find a pattern to your cycle, provided u have a regular cycle. So what u discovered is that when AF is over, your temp is still low, so u shld BD. And sometimes it will drop to a lowest point, that's your O. Once u O, temp goes up and sustain till your AF comes again. For me, it's v obvious, 35.x I will have O and AF, 36.x is my normal temp. Interestingly my this month temp has a very high variance, my lowest point went as low as 35.46 which for the past months was only 35.9 and I tested positive on that day too, hopefully got good news