OPKs and fading lines

Mirella
So clear blue advanced OPK.... I've had the blinking smiley face for 5 days now.... This is what my sticks have looked like since I started testing about 9 days ago.... The smiley face is blinking but the line seems to be disappearing and I never got the solid smile... I hate these tests... It was spot on last month for ovulation... Bc I got an ultrasound and I was ovulating at the time... But now!? What's going on w those lines! Any ideas?