Life gets easier, I promise. Right now for you it's a good day if everyone is alive without stitches at bedtime.
My youngest will be 3 in August and I am just now occasionally thinking, "This was an easy day." On rare occasions. However, I am experimenting more with healthier foods. Actually, I'm amazed how much time I now have for that. Here are some tips that might help:
Get some good cookbooks and look for recipes that might work for you. I REALLY, REALLY like the weight watchers cookbooks. The food is really healthy and very yummy. Many recipes are simple to make.
As you find more recipes that work for you, keep a list of dinners that you want to do again. I lost my handwritten list so now have it on the computer on excel. Some day I may include ingredients to facilitate some use I can't think of at this time.
Shop once a week. Make a menu for the week, shop for ingredients you need to make the menu, and post the menu on your fridge. If you know one day is really busy, you can plan a simpler meal (say bean and rice tacos) for that night. On days without plans, consider a recipe that you can start in the morning.
Start making dinner in the morning if the recipe allows it.
Don't get too fixated on the food groups at each meal. Think about over the course of the week.
Do try and eat "a rainbow of colors" at each meal. Serving fresh fruit with a meal helps the rainbow.
Try crockpot recipes. For awhile I was mixing the non-liquid ingredients after the kids went to bed, putting it in the fridge, adding the liquid in the morning, and serving for dinner.
Go gluten free. We tried a gf diet with our daughter who has a speech delay. Three weeks later he speech took off. We don't know if there's a relationship or if it's just a lucky coincidence. We decided to stay gluten free because it's pretty easy for us and it's a really healthy way to eat (as long as you don't buy gluten free substitutes like pretzels, muffins, breads, etc.) Automatically I had to stop buying drive-thru french fries because they are all coated in flour. We switched from whole wheat pasta to TInkyada brand rice pasta which tastes so much better and is still a whole grain. This may be a bit complicated for you now, but going gf forced me to start making my own veggie broth. (I freeze it in ice cube trays then ziplock brand bags which are BPA free.) Gluten free eating (without using substitute gf products) just forces you to eat healthier, but really doesn't take any more time.
Learn to use your freezer. When we have leftover brown rice or tinkyada pasta, I put wax paper on a cookie sheet, spread out the pasta or rice on the sheet and freeze. Once frozen I put it in ziplock bags. For a quick meal for the kids, I microwave rice (add some frozen veggies, a scrambled egg, tamari and sesame oil and they have fried rice.) The pasta goes in a bowl with a bit of water, microwaved, and there's a quick pasta lunch. I make my own pesto (Trader Joe's brand has black pepper--a family sensitivity.) I freeze leftover pesto in ice cube trays, transfer to ziplock bag, then microwave portion size when I need it. Same with red pepper and basil sauce. (I actually need to take mine out of the trays tonight.) I made up a batch of beans in the crockpot, dried on the wax paper covered cookie sheet, froze after dried, measured into ziplock bags, then put back in the freezer. When we have tacos (a quick meal) or cheese crisps, we can just take out how much beans we want for dinner and put the rest back in the freezer. Here's a thread I started on freezing foods:
http://www.mothering.com/community/forum/thread/1313694/what-foods-do-you-freeze
So, you will have more time to cook more interesting foods some day. My 5 year old is already becoming an excellent cook and my 2 year old is starting to cut mushrooms with a butter knife. Spending some of your precious free time finding simple, but tasty, recipes is probably your best plan right now.
Red Pepper and Basil Pasta Sauce (my adaptation of a weight watchers recipe.) This is my 5 year old's favorite pasta sauce.
Chop 1 onion and 1 red pepper and saute in olive oil. When soft add one clove garlic and at least a cup (more is better) of fresh basil. Saute for a minute. Add 3/4 cup veggie broth. Simmer 10 minutes. Add 1/4 cup milk. Place in blender (an immersion blender didn't work for me.) Serve over pasta with parmesan cheese.