Now that you've had a few months to settle in as a family together, I'd start looking into delegating responsibilities to the children and your husband. No mother can do the work of 5 on her own. Especially with a toddler on hand.
At our house, everyone is required to make their own bed first thing in the morning, and toys and hubby's work papers must be put away before bed at night.
After everyone brushes their teeth and washes up in the bathroom, they need to take a paper towel to the counter and floors to wipe up water and wipe up any toothpaste spots etc. with a disinfectant wipe. If there are dirty towels piling up or the hamper is overflowing, they have to straighten up, and hubby takes the laundry to the laundry room.
No room can be left a mess before bed. So for example, if the hubby and/or children were in the family room, and there were pillows or toys tossed about, they have to have things back in order before they leave the room. If guests come by, after they leave, tables are to be wiped off/dusted, the carpets are vacummed and dishes are loaded in the dishwasher immediately, before anyone can go to bed etc.
After each meal, each family member takes turns during the week and is responsible for loading the dishes in the dishwasher. Before each meal, a family member is also delegated to empty the dishwasher and put dishes away. If needed this person also sets the table. Doing it this way keeps dishes from piling up, and the dishwasher always open.
I think delegating housemembers to keep on top of these basic but major areas make all the difference in the world. In the big picture, all your doing is making everyone responsible for cleaning up behind themselves, instead of leaving it all to you. IF the house is generally neat, and clutter free, the big cleanup duties are much less overwhelming.
Age is not a factor with any of these expectations. Even your 3 year old is ready to start taking responsiblity for small tasks. He may not be able to do dishes, but he can straighten up his room, and wipe up behind himself in the bathroom. Our little guy puts his own toys away when asked, and does a great job at it. In fact, it is second nature with our kids now that after they're through playing with something, it is to be put away. If they're cleaning up even the smallest amount of mess, life will greatly improve at home.
As for the bigger tasks, pick a set day or two (if you have big loads) for laundry. Keeping it set on a specific but unchangeable day each week. For example we do Wednesday because it is the middle of the week...about the time you need more fresh clothes. This will help keep the loads small and manageable, even for a household of 5.
The older children can be in charge of this if you give them good instruction on sorting and how much detegent to use etc. They should also fold everything right away to keep clothes fresh. Assign a "basket" to each house member, and they can fold and sort the clothes into the proper basket. Then you or dad can bring the clean clothes baskets to the right room, so the clothes can be put away. Make everyone put their own clothes away.
Avoid letting clean clothes pile up in the laundry room. People will get complacent and just keep wearing more fresh clothes from the closet. You will find quickly that you go through even more clothes this way, making laundry day daunting and awful.
Reserve an entire day each month dedicated washing to big heavy stuff like comforters and blankets if you don't dry clean them. This should be an adult job. Don't incorporate this type of stuff with your main laundry because it will set your schedule off big time. (dry time for one)
Mopping and sweeping can be done daily as part of kitchen/bathroom cleanup duty.
Another thing that may be throwing you off, is mealtime. PLan meals every two weeks...once a week at a minimum. Avoid deciding day-to-day. This can be a time waster. If you plan ahead, you can budget better, and often prepare alot of the food on the weekend, so that all you have to do is heat it up during the week. Invest in a good crockpot. These are a life saver for those who work. Just put the ingredients in the pot before you leave for work, its cooked and ready to eat when you get home. Lasagne, casseroles, quiche, etc. are all things that you can make over the weekend and freeze for during the week. Soups are another great make-ahead meal.
If you're kids take lunches to school, have everyone make their own lunches after dinner, the night before. This will save time in the morning, you can monitor what they're preparing, but they have some say in what they're bringing.
Keep healthy but low-mess easy to prepare snacks on hand for the kids during the week. Fruit, popcorn, etc. are all good, and they don't make a mess in the kitchen.
Last but not least, when you have a weekend to spare... go through the house and get rid of anything you don't need anymore, and then reorganize your shelves. If you assign a "home" to everything, keeping your home organized will be a cinch. The biggest contributer of a disorganized home is unnecessary clutter. If you have no place to store something, and don't really use it, get rid of it. If it has a "home" then people will know where it belongs and will put it there when they're not using it. Likewise, they'll be able to find it when they're looking for it.
In order for this theory to work...invest in good storage cabinets or shelves. We keep alot of our kids' toys in locked cabinets to cut down on the amount of loose toys around the house. For the items with lots of little parts and stuff, keeping them locked cuts down on choking hazzards and big messes becase they have to ask for these things. It's easier to monitor and control tiny pieces this way.
While having a clean and organized house is a reward in itself, be sure to reward the children and even your hubby for their dutiful support. Allowances and even special treat incentives can keep the momentum going and cut down on grumbling. Have contests, and give aways to make things fun.
I hope some of these ideas help. They helped us.!