This probably means nothing. lol. Sometimes people sub-conciously dream about topics, just because they have been thinking about them good nor bad. For example. a person could dream about the oil spill because they've been exposed around it alot or have been recently thinking about it.
Most likely, it means nothing...but it could also mean your desire for a little girl. Maybe there is doubt that you could have had one, because in reality as the male has an X and Y chromosome and Women and X and X chromosome...crossed there is a 50/50 chance for a girl. In your mind you knew it was possible, but didn't SEEM probably. It's not your fault if this is the case.