Help!

Lydia • We are expecting our second child in May 2017💕My husband and I are expecting our first child a baby girl in May 2015💗
My cycle days are usually 24-26. Now I'm on day 33. I've taken 1 early detection pt every few days and BFN. How could this be? I'm taking the test in the afternoon. Does it realy make a difference if I were to take it in the morning?