My go-to in that situation would be big-pot meals. Make a big pot of something on the weekend when you have more time and energy, then freeze single-serving portions of it in Ziploc containers (not bags, but the little plastic bowls with snap lids). Then during the week when you're wiped, all you have to do is pull one out and heat it. Add some bread & butter, salad-inna-bag, and fresh fruit, and you've got a quick and easy dinner that's no more work than a ready-made frozen dinner, and cheaper and healthier to boot. If you want suggestions on dishes that freeze well, I'll be happy to offer some -- we do this regularly for the nights when we just don't have time to cook.