Hire a high schooler or neighbor home from college to either run errands for you or watch the kids while you run errands. Prioritize and assign items for each family member. Make double batches of everything you cook. Freeze a batch for days when you're rushed. Cook what will make a variety of dishes.
Ground turkey can make burgers, spaghetti, meat loaf and tacos.
Have the courage to say no. Buy prepared cookie dough. It's a great time-saver. Plan time to be good to yourself. Maybe that means a pedicure, quiet time at a coffeehouse, or a relaxing bubble bath.