Bbt pattern and opk ?

So I have charted for 2 months now. The first month I had noticed a large dip in bbt the day before a positive opk. Didn't get pregnant that cycle but charting again this cycle and yesterday had the large dip again with back to normal temps today and opk is still negative and much lighter than yesterday's. Digital was negative but the wondfo was almost positive. All were negative today. So is it possible I have missed my surge in a days time? First pic is last cycle, 2nd is current.