Emz, that little girl is healthy and happy kicking away in there and it seems she is letting you know. Big deal if the chromosomes aren't exactly right.
She will be born because of the magic of you and DP and everyone will love her, but no one as much as you. If there is Downs, it will be secondary to the fact that she is your very own baby girl.

Abby is a beautiful name and she has chosen her parents wisely.

Good luck with everything, see you around the forum!