Wedding dress disaster

So fun story, I've had mono the last several weeks, and though I do have my dress, I had it custom made based on my measurements and...Idk what on earth happened. But it fits everywhere except for the chest/shoulders. My wedding is on 2/15/2025, so like...this coming Saturday. I have no idea what to do. I totally failed with getting my dress situated on a good timeline, and now I'm stuck with a dress that is meant for a much larger chested woman than me?



It's gaping, as you may be able to tell, and the cut is WAY lower than the original picture from the website.
I'm genuinely freaking out. Is this fixable within a week, or do I need to figure out something else...and if something else, what do I do???