LOL, if you think of it, you're trying to do TWO full-time jobs now: child care and homemaking. Something people always remind me is that your house will NOT be a showplace, and the only way to be happy and have more peace in your life is to accept that your house will be cluttered and less tidy than you would prefer. Your kids will be young for only a short time. My oldest is 18 months and I'm amazed at how big and competent he's gotten in the blink of an eye. Your kids won't care if the house was clean - except as a clean slate to make some "art" on - but they will remember that you were available to read stories, to make art, to eat snacks, to play in the yard, to tickle and goof around. That's not all of life, but that's sometimes the trade-off we make.
I'm still learning how to take care of the home while my son is awake. I used to put off everything until he was asleep, including eating, but he's only napping once a day now, and I'm also 8+ months pregnant so I need all the sleep and food I can get! So, I make sure he sees me work during the day, and try to involve him how I can. I'll ask him to put away Tupperware containers, for instance, or to help me put away groceries. He likes to help with laundry, by pulling clothes out of the hamper to hand to me or putting bibs and washcloths in the basket where we keep them. About half the time, things aren't done the way I'd prefer, but I always thank him for being helpful and he loves to help and will clap for himself after completing a task.
So, they'll learn the importance of housework and helping around the home by helping you do it, or even being in the same room and playing independently while you work. Children don't need to be constantly entertained - given the freedom, they'll find ways to keep themselves occupied. (And a bit of nudging on our part - for example, after about 18 months it's okay to tell a child to "go and play" while you finish a task, as long as that's not the only thing they hear when they want to spend time with you.) And your oldest is the age where helping Mama is the greatest, most important thing in the world and ever so fun, so take advantage of it! ;-)
And finally! Take time during the day or the evening to do something JUST FOR YOU. You are crucial to the smooth running of the home, the axle of the wheel, the well that refreshes everyone else. I don't think people realize just how important a position we homemaking women hold, not even the homemakers themselves. So, take some time to replenish your well, and to do something you enjoy, like a hobby or reading a novel or finding some way to go out with girlfriends occasionally, without a spouse or child along. Just to keep the "non-mom" parts of you alive and refreshed. My husband, evil patriarch that he is, often orders me to sit down and not work and to do one of my hobbies while watching a movie, because he knows I find that very relaxing and enjoyable. So I meekly obey....