Ovulating Test

Rebecca
I am after some advice. I have been TTC for 7 months and this month decided to try Clear Blue digital ovulating tests.
Following this app, the predictions said I was due to start ovulating period Monday, with Wednesday being the peak/highest percentage. I have been taking ovulating tests every day from Friday 31st Oct around 5pm (today was 3pm) all through to today (CD18) and still have not had a smiley face to say I am ovulating. Is it too late in my cycle to catch now? When I update my app to sync negative ovulation test is just moves my ovulating day out another day! I'm so confused, but it might explain why I haven't caught yet it I have been trying on wrong dates