You didnt do any thing wrong, it sounds like there was a problem with the fluid bild up, and that the foal wasnt strong enough to help or, I am not sure why the sack wouldnt rupture like it should, I have never had that one, a friend of mine said when heres started she was having trouble and her dad went in and broke it and pulled it for the mare. Sorry to hear about it, has she dropped before, or was this the first one?