Opk question

betsy • 👼 6/18**👼12/19**👼8/19**TTC for our 🌈**

Hey ladies!! So I have had positive opks for almost a week now and aunt flow is due in a week. But my question is, is it normal to have positive opks for a week? And when I say that they have been positive, they've all been extremely dark like this one. And the reason I'm asking is because I've never been this long with positive opks.