OPK from low to peak in a day?

Libby • Married 2 years to my best friend and Expecting baby #1 a few days after our 3rd anniversary!
Has anyone had a clearblue digital ovulation test go from low fertility to peak in one day with no "high" days? I started Tuesday and had a low, Wednesday had a low. Fertile week was to start today (Thursday) and I got a peak OPK. I haven't used these before so I don't know exactly what I'm doing...