Ovulation

Alicia

So I was still a little confused with the whole ovulation strips and how one could ovulate early? So I went ahead and used this website. Can this be true?? Glow has be super all over the place since first my fertile window was 8/27-9/2 with a peak on 9/1. Then when I got a positive opk it completely changed my calendar saying fertile window 8/21-8/27 with my peak 8/26. So am I 7dpo or 11dpo??? Also AF is due 9/9