*hugs* I'm so sorry you're dealing with this. I'm in the same boat, with 2 boys already and a baby on the way (I'm 21 weeks, so looks like we're due around the same time!). At my 18 week U/S, the tech was very unsure about the gender because baby just wasn't very cooperative. BUT she did say hesitantly, that if she had to lean one way she would say boy. [:'(] The only reason I didn't stop her from telling me her 'guess' was because I thought for sure she'd say girl. That, I could've handled. She then pulled up a pic from earlier in the U/S and pointed to what *may* have been a penis and scrotum, although I really don't know. That's what it looked like to me, but she said it was not from the angle that she likes, and the 'penis' could have been cord. So I've been struggling for the past few weeks thinking that it must be a boy, and really trying to prepare myself for it. I've scheduled another U/S at a private clinic for May 2, so I just have to wait until then, although it's been incredibly difficult.
I just wanted to offer you some insight into my story as well. You are SO not alone in your feelings, I feel almost exactly the same way down to the reasons for wanting a dd, and the disappointment of not ever having one because I'm the one who doesn't want anymore kids. Although one thing that's different between us is that I am a total girly girl (always have been), and wanted to have one of my own. I know if I had a DD, she could be a tomboy and not into girly stuff at all but a girl is a girl, there's no two ways around it. At least I'd be the mother of the bride one day (probably ).
Anyway, hang in there. I know it must be incredibly tough right now, but it will get easier to accept your new little boy as time goes on.