I am seriously freaking out - I just had my first fitting and the dress doesn't fit. It's too small. I've been in tears all afternoon

I bought the dress at a bridal show, and from what the lady at the alterations place said, when I tried it on, we didn't have it sitting properly on my ribcage, so we could zip it up then. She moved it to where it was supposed to be and now it won't zip. Because of the way the beading, ribbons and etc are, she can't just add more material or take the seams out.
She said she is going to have to cut off half the zipper and make the remainder of the back a tie-up so that it can be adjusted to my size. Whether I gain weight or lose weight, she said the tie-up back will be able to be adjusted.
I'm just totally feeling like a big fat cow right now and completely worried that the dress isn't going to look the same or I won't like it with the tie-up back. Even though that's pretty much my only option.
*sigh*
BFP #1: 5/20/12 ~ EDD: 2/20/13 ~ Betas at 221: 5/24/12 ~ Betas at 917: 5/29/12 ~ M/C: 5/29/12
BFP #2: 10/17/12 (13dpo) ~ EDD: 6/29/13
Beta #1 @ 2164: 10/22/12 ~ 1st u/s: 10/26/12 = empty ute
Beta #2 @ 7610: 10/26/12 ~ 2nd u/s: 10/30/12 = measuring at 5w6d
3rd u/s: 11/5/12 = HB of 150 ~ 4th u/s: 11/27/12 = perfect wiggly LO!

"Everything will be okay in the end. If it's not ok, it's not the end."
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