important dress question

FOR THOSE BRIDES WHO HAD A COTURE FITTING GOWN DID IT LOOSEN UP ON YOUR DURING THE DAY?
I FEEL LIKE MY DRESS IS SO TIGHT AT MY WAIST AND ON MY RIBS BUT THE BIRDAL SHOP KEEPS TELLING ME THESE DRESSES ARE MENT TO BE TIGHT IN THESE SPOTS TO KEEP YOU IN PLACE. SO RIGHT?

how tight is it? yes it should be form fitting but you should also feel comfortable in it at the same time. I had lost weight between final fitting and day of wedding so it was a little bit loose to begin with, dont remember it getting even more loose though .