I haven't been in this situation but maybe it's just a grass is always greener type thing? I'm sure your dress is beautiful, maybe it just other stresses and nerves manifesting itself this way? Especially since as you said the dress was fitting quite large and you had a hard time envisioning the final fitted product? You fell for this dress once, so like the other girls have said, once you have everything in place I'm sure you'll get those feelings again!