OMG MissAngel. I know exactly what you're going through! I took my engagement ring in to be resized a fortnight before my wedding and found out a week later when I went to pick it up that it had been stolen from the jeweller
it was one DH had desgined himself so couldn't just be replaced
I'm so pleased the woman is getting a new one made for you and I don't want to freak you out as I'm sure everything will be perfect but to be on the safe side why don't you take bizzy up on her offer to borrow her dress so you have a backup.
As I said about my wedding disaster there's always bound to be something that goes wrong and you're very lucky that it happened before the wedding with time to fix it. Now that you've had your wedding disaster everything else will be perfect 