Opk help

I got my solid smiley Face on the clearblue Advanced digital on thursday Morning, and usually my Shift in temperature Happens the next day after I get the solid smiley. I still haven't had a surge in temperature and it is now Saturday morning so 48 hours later.... I can feel a huge follicle on my left. Will it just not rupture? I am on cd17 today... I usually ovulate on cd15-16... Thanks for any advice. X