Ovulation tests

Sarah • IVF success! Boy Mum 01.07.2020🤱🏼

This will be month 5 ttc but I have Had irregular periods since I have been off of my bc. So i have been unable to track my cycle. It seems to vary from 40-46 days. This month I feel like I’m finally getting a glimpse of it because I started using ovulation tests. Do I have to wait for it to be a dark line or does this mean I’m ovulating?