PLEASE HELP ME πŸ˜«πŸ˜’πŸ˜£πŸ˜–

Unique

So I am supposed to be in my fertile window according to the <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a> but I have been taking OPK test since yesterday and they have been coming back negative so I’m so confused.. can someone please explain all of this to me?!? Please!