You can do this!!! While finances are something to be upset and nervous about as long as you and your kids have your health and each other you got this bump.
When on a really tight budget being as self sufficient as possible in every way. You tube is your friend for fixing things you never thought you could. As of for food grocery stores differ greatly in price - get online and register with your local stores so you can see weekly specials at each as well as down load digital coupons (no more clip and carry). Never shop without a list and plan meals for the week. How to stretch a dollar around the world starts with trimming waste. Here is what I would do for 3 days of meals on a budget. Start with a large Roast chicken for day one. half will feed 3. Next day the other half is chicken salad. Save the carcass and the next day use the carcass and chicken scraps to make homemade chicken noodle soup/ chicken dumplings. While I prefer fresh vegetables they can get expensive and go bad. Look for deals on canned veggies - also dried beans are very inexpensive. Ok so on day 4 when everyone is chicken out I would serve spaghetti Aglio (spaghetti, olive oil, fresh garlic, and parmesan cheese). Make a double batch because the next day I would make traditional spaghetti and bolognese (On a budget i would get jar sauce as its less expensive, and then doctor it up), and will be extra yum on top of leftover spaghetti aglio. Now up to day 6 tonight I would make enchiladas with the 1 lb of grand beef or turkey leftover from the 2 lb you bought (used half for spaghetti) use old el paso enchilada kit which is less than $5. For sides yellow rice (dried) and a can of black beans. Finally on day 7 I would look at the staples in my fridge and probably do "breakfast" for dinner. Finish off the dozen eggs, a protein in bacon or sausage, and waffles or pancakes from scratch. Very inexpensive meal.
Keep in mind that most of the time (some exceptions) making your meals from scratch is far less money than prepared foods.
I am sure you will do fine and get a hang of it. I love to cook and make almost all our meals we seldom eat out. If you need ideas or recipes feel free to PM me.