Ultrasound went different

Bree
So we asked about the gender. I'm 15.4 weeks. And he said he sees a nub, but he doesn't know if its a boy for sure. And we seen the cord. So what else could this nub be? I don't have a picture off hand itsbon a CD. I'm just confused. So on the picture he typed (.........boy?) I guess I'm just worried now.