Feeling slightly confused

I know you can ovulate later but my cycles are pretty regular and if it’s later it’s not more than a day. I started the clear blue advance ovulation test. Normally I would get 3/4 days of high then my peak. It was always the day after I started testing is when I would get my high. I have been testing for 3 days and still a big empty circle ⭕️ according to this app I was supposed to start my window yesterday. 🙁 I know it isn’t long but it’s just odd that I haven’t gotten anything yet since I’m usually so predictable.