So I FINALLY got EWCM yesterday

around 2:30 or so after days of spotting but according to FF I've already O'd just based on my temps. Yesterday morning my BBT was 96.8 very low and I thought this was weird but it was low a few days ago. When we got home I took a OPK and it was negative(I think) but it was the darkest one I've had so far. What do you all think? Did I O yesterday and is FF wrong or am I wrong?
Here's my chart.
2a71d1 Ovulation Charts