Could I be pregnant?

Me and my SO had sex like 3 days ago, and he came inside me. I'm not on any birth control or anything. Also, according to <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a>. that day was part of my fertile window..could I be pregnant? I have been hoping for a baby for a very long time. #Praying