Fertility window and ovulation test

My fertility window started Sunday and I took and ovulation text today and it said I wasn't ovulating. Anyone have experience with this? Also I stopped breast feeding my first one last September and this past February my periods have become lighter and not as long. I went from flowy regular 6-7 days to very verrrry light 3-4 days if that. And extra extra cramps before and after. Eek. I'm so confused.