Thanks so much, everyone! I've gotten nothing but rolled eyes when I ask people I know whether or not this could be a girl, so I appreciate the fact that you all took the time to really look. I'm sure many of you can relate to my feelings of disbelief and uncertainty, no matter how obvious the answer appears to be to everyone else.
I forgot to mention that I had a scan at almost this exact same gestational age with my second daughter. While I saw a few angles with her that looked a little more boyish, the majority of the views just screamed girl. We even saw the three lines fairly clearly. There was nothing that looked remotely like what I saw with this baby. EVERY single angle was boy, boy, boy. I've also taken a look at some of the wrong guesses around this stage that are posted on this board and others, and I have yet to see one as convincingly boy as mine turn out to be a girl.
But there is always going to be that little seed of doubt, I guess. It doesn't help when I read about all the things here that could have been done to sway and I know we did NONE of them. We weren't even trying to get pregnant. If anything, our timing and my total lack of fertile cervical fluid should have guaranteed us another girl. It just doesn't seem possible that we could do everything "wrong" and still end up with a baby boy.
Anyway, I'm rambling ... thanks again for all your input! More replies are always welcome too.