Positive then negative Ovulation Test?

Christina
Please. I'm seeking some guidance as I'm losing my ever-loving mind trying to track and find our window. 
I've been tracking BBT, CM and using ovulations sticks. The app indicated I would ovulate this weekend (18th/19th) but on Tuesday I had fertile CM. So, Wednesday morning I took an ovulation test and it was positive. I expected there to be a rise in temperature this morning, but there wasn't. Out of curiosity I took another test and it was negative. WHAT? This is so confusing and frustrating. Of course googling this gives nothing definitive; however I did read it could possibly be an anovulatory cycle? So I was preparing to ovulate, but didn't? 
Has anyone else experienced this? Any insight is appreciated.