Clearblue digital ovulation tests

Amanda • I`m 28 years old. Married since 2011. We have a 5 year old son. Baby #2 due in nov2016!
So the box says that I'll get a blinking smiley face for two days and then a solid smiley face for two days. But I've gotten a blinking smiley face for the last 3 days, does anyone know why that could be? TIA :)