M.M.
I don't know about how to "get over it" since I only have one little boy. But I just wanted to tell you that I felt exactly the same way when I was pregnant. I grew up in a house with three brothers and I was a real tomboy. I was terrified of having a girl, and even though the doctor kept telling me that I was having a boy I was still scared. I wouldn't even let any of my friends buy me anything blue b/c I thought that it would somehow jinx things and I would end up with a girl (I try to blame that on pregnancy hormones =). But I hope that even if I had a girl I would love her just as much as I love my son. And, by the way, my son is nothing like I expected him to be, but everyday I love him more.
I hope this helps.