Can I still get pregnant if he didn't finish?

Hey ladies, according to this app my fertile week started the 18th. My SO and I had sex the 17th (he ejaculated inside me), the 19th and 20th (he didn't ejaculate at all). I am kinda hoping all that stuff people say about precum is true or that his swimmers are strong enough to stick around from the 17th. I'm looking for answers about how likely it is that I could get pregnant this cycle? I know the week isn't over yet but I'm really excited, I want a baby so badly!