Do your meal planning with your calendar or dayplanner in front of you so that you can see what's logistically feasible for different days! (For example if I have to go to the dentist, Bible study, and then take my son to kung fu practice on top of other stuff, then that's a left over or crockpot night!)
I write the days of the week with 4 lines between them (so I can write a breakfast, lunch, and dinner on each line, and a blank line before the next day). Plug in what's easiest for you first: for breakfast Monday thru Friday, my husband just wants cereal and a banana, so boom, that's plugged in easily. To change it up a little for my boys, I'll have yogurt for them on Tuesday and eggo waffles or something on Thursday. Saturday is more relaxed and less of a morning time crunch, so we have oatmeal. Sunday is a hot breakfast: breakfast burritos, pancakes and bacon, etc.
Then I do categories: chicken, beef, pork, vegetarian (or at least mostly veg), seafood, a soup or stew. That way it's not the same old stuff all the time. What soup or stew that week? Minestrone, gumbo, chili, chicken noodle, vegetable beef, etc. That will last at least 2 dinners and maybe a lunch (if more than that, freeze some and you've got another meal for another week). It might be chili and cornbread one night, and then chili dogs later that week, or a beef stew and sliced bread one night, and a beef pot pie later that week. Your beef could be a pot roast (minimal effort: wash stuff and stick in a bag with a seasoning packet, can of rotels, and a can of cream of mushroom and let it sit in the oven awhile)--you could have with carrots, potatoes, rotels, celery, onions, and gravy one day and then you could slice it up for a nice sandwich (with some gravy) and provolone cheese another day.
It's also good to have one "oops" meal in the freezer just in case it's been an unexpectedly bad day and you just don't want to cook. I keep a Stouffer's party size lasagna and some bread in my freezer, and can always make a salad real quick if I'm not in the mood or don't have the energy sometime. But once you plan out your dinners, you can then plan out your lunches: if it's not likely to have leftovers, those are pbj, meat and cheese, grilled cheese, cucumber and feta, "etc" sandwiches, with fruit or veggie sticks, or pasta salad, soup, pita chips and hummus, or whatever. On a day after you're likely to have leftovers, you can have a lunch portion of a leftover as an option.
That's how I do it, at least.
Also: try to cook more than you need as you can, if possible. Since you're pregnant, I'm thinking that instead of making 1 batch of meatballs for spaghetti night, you make 2 batches and freeze one (write what it is and date it), you can begin stocking up for the end of your pregnancy and when you return with the new baby! For example, sometimes I'd make a chicken tortilla soup (without the tortillas yet) in a crockpot while I was cooking something else for dinner. When the soup cooled down to a safe temperature, put it in a ziploc freezer bag and lay it FLAT to freeze, and it's like a file folder. Those extra steps now will be a such a huge help later when you aren't sleeping and have a newborn (AND the rest of your family to attend to). If you want ideas on what to cook/store for post pregnancy, message me.