Take care of yourself. It's always important to eat right, get enough sleep and exercise, but it's especially important during times of stress. You'll feel more energized, you'll be able to think more clearly and make better decisions. Besides, who wants to see a bride with dark circles under her eyes drag herself down the aisle?
Keep things in perspective. The most important thing to remember is that the wedding is only a one-day event. It's just a party to celebrate the beginning of a life together. Too many brides feel enormous pressure to make the wedding perfect and they forget about building a solid marriage. Don't lose yourself in the details of this one day. You have a lifetime of new memories to create, this is only one of them.