Periods & Glow

So I'm a bit annoyed .. This app works for me usually and is pretty spot on when predicting my cycle .. But my issue is that last month April 29/30th my bf ejaculated inside of me while glow said I was ovulating.. Okay so I know to watch out for my period this month.. Usually comes around the 17th even glow said so.. But every time my period doesn't show up on the day glow predicts it just adds a week to my cycle.. So idk if I'm late?? Or am I even ovulating when glow says I am???