Positive OPK day before your AF?

Mamaof4 • 4 kids ages 11, 10, 9 and 2 years old.
So AF is de tomorrow. Checked CM and got an almost egg white type, cervix is higher than yesterday so I decided to randomly take an opk. I was shocked to see positive. Did it twice, digital and got smiley faces both times. No sign of AF yet. Anyone else experience this?