I know what you mean Danni.... but really once you see that they are healthy and all is well that feeling subsides a little.... I was like that if Jacob was a girl, really didnt want a girl for some reason.
Just remember that when he or she gets here that you are blessed to have this healthy little bundle in your arms
Just work through these feelings in your mind and heart and realise that they are not the most favourable of feelings for your own well being and the babies.

Good luck darlin!!
xoxoxoxo