Do you use the normal OPK or advanced OPK?
The normal OPK only measures the LH hormone and you only get solid smileys. The advanced OPK measures two hormones (estrogen & LH) and you are suppose to get a flashing smiley for a couple of days before you get a solid smiley.
A flashing smiley means high fertility - i.e. Your body is gearing up for O and a solid smiley means peak fertility and you'll O in 12-48 hours!
Each cycle can differ. My cycle before last I had 4 days of flashing smilies before my solid smiley. Then I ovulated 2 days after getting my solid (I temp as well so I know exactly when I O).
My last cycle I went straight from nothing to a solid smiley. Again I ovulated 2 days after my solid smiley!
So basically - yes if you got your solid smiley today then you may not ovulate until Saturday. Do you temp so you can make sure?
Also how do you put your OPK results into FF? I use the OPK monitor and mark them as 'low', 'high' or 'peak' fertility.
Also I read a fertility book and the author and her friend, who had both been TTC for a while, got pregnant the month they DTD the evening they got their solid smiley, again the next morning and evening, again the following morning, and again the morning after that! I'm yet to manage that sex marathon but thought I'd share with you!