Hi there-
Do you enjoy eating at fancy restaurants or watch Food Network like a fiend? Then go & savor V&A. Don't let cocktail dress shopping put you in a pissy mood! Pull anything on that meets their dress code

& deal with the diet issues post-vacation. I recommend an empire waist sun dress or a high end skirt with a twin set. Plus these items can be used post vacation while I never ever wear my cocktail dresses... Try anything from Chicos, J. Jill's, Talbots or Cold Water Creek. All of these stores are trying to cater to poor souls who like style but lost their size 4 bodies while out living & experiencing life! Ummm, yeah, I'm waiting for a J. Jill box to get shipped to my house right now!
It sounds that you are trying to ruin your own vacation. You mentioned you run a business, are a parent, and run a household. You sound like a pretty big success to me! I think it it Covey (7 Habits) who recommends you have to put time into a relationship so you can later take it out. Vacation is investing in your family. You've earned it - financially & mentally. If you still don't think you've earned it, as a member of your family, you win the vacation de facto.
You are stressing yourself out! If it rains, go play in the Epcot jumping fountain without a poncho. Jump in real puddles. Have everyone buy WDW
crocs and take a picture of everyone's feet in the rain for a holiday card. Go to the movies. Ride Splash Mountain in the front seat! Get in the hot tub or pool no matter your swim suit size or if it is raining. In fact, splash your kids and play with them. Hang out in the hotel lobby and make up stories about the people you observe. Ride the monorail in a circle over and over again. Sleep in! Eat a long & lazy breakfast. Get up one morning and let your kids choose the day.
Be good to yourself. You've earned it.