OPK strips

Glow says I've been in my fertile window and that today is peak fertility... I've been doing opk strips the last 3 days and they are super negative, like barely even a second line. Shouldn't they be getting darker? Im on CD 11 and Glow told me to start testing CD 8. Will I all of a sudden get a positive opk? It just seems like they're getting fainter and fainter 🙄 hopefully the app is just way off and I still have a few days til I actually ovulate!