Focus on putting one foot in front of the other. Small steps in the right direction rather than trying to achieve too much big stuff. E.g. 5 mins a day of life admin / paperwork, 5 mins of decluttering, clean one small area, etc etc.
Routine is helpful. Try to get out of the house at least once a day even just around the block.
Get whatever gadgets you can that help e.g. tumble dryer, dishwasher etc etc - anything that cuts down on the daily grind a little and makes things a little easier. Shop online for groceries (shopping with kids is too difficult). Days out don't have to be big, full on affairs - just a visit to the park is good enough and if you don't manage it and have a day of TV then go easy on yourself.
Use screens as often as you need to! And don't feel guilty about it.
Declutter like a mad woman, because life is a lot easier when you have less stuff with kids around.
If you and the kids need a day off school because everything is too much again take it. Sometimes the school run is too much to deal with and historically I took occasional days off with the kids because I couldn't deal with it and was so knackered!
Preparing the night before for school (lunches, uniforms) and doing them in batches to save time is also helpful (e.g. 2-3 days at a time).
Depending on your financial situation it always makes sense to watch your money as a LP. I am very careful because I have to be. e.g. charity shopping for kids clothes etc - buying in advance for older ages, because when you need something you might not find it.
Occasional basic holidays away from the house also good - just in the UK - a little break from your regular environment and all the housework.
Get to bed early whenever you can. You will feel loads better.