Help? So confused opk

Okay so I posted the first opk yesterday and it looked pretty close, then I took the second one closer to bed time and it was way darker. Took the. Third one this afternoon and nothing? Did I miss my chance? Hubby and I did bd last night when I got the surge and this morning. I just ended my period today. And I plan on taking another tonight. Anybody know what could possibly be going on?