OPK Question

Tiffany🌻 • Pregnant with our first...due June 2018 ❤️
Help! I'm so confused. I thought I got a positive/peak on CD 18 and now I test today on CD 20 and that's how it looks. What on earth is going on?? Normally my opks are colored on the test side for like 3-4 days total. I'm trying Premama Fertility this month and I'm not sure if that's what's affecting it but does anyone else have experience with strips colored like this and ended up with a BFP? Thanks so much!! 🙏🏻 Oh and I normally get my positive/peak on CD 13.