2nd month this happened to me! WTH!

Amber • Mommy to Bryce 12/2/14. Baby #2 arriving May 2017!
So I'm on CD 17 & finally hit peak on opk stick & CB digital. This morning CB digital gave me a low reading & opk stick gave me a very positive opk (so positive the test line is darker than the control). This happened last mont too!!!! Also bbt has not increased yet! Some one please help. Am I not ovulating :(