Do you have a schedule? I have heard good things @ the books Managers of their home, chores and now they have a homeschool one too.
For us, I made an excel sheet with my name and all the kids names across the top. I have the times listed down the left side and then in each column I have what each person should be doing during that time slot. This is my master schedule. Then I made one similar for school subjects. I like having all the kid son one sheet so I can see where everyone is at one time. Each child receives a sheet with just his/her own schedule that they keep in their binders.
As for the weekends, I finally started having a Sunday night organizing hour(or two lol). We get the laundry sorted for morning, kitchen spotless, house tidy etc so Monday morning isn't so stressful. I had always tried to do as little work on Sunday and it made Monday unbearable.
For school, I would definitely try to combine as much as possible. At your children’s ages I would only do math and language arts on grade level and combine the rest. I used to try and work with the oldest first, but the younger kids all needed/wanted me then and it was chaos. This year I have the older ones doing independent work while the younger ones do some fun stuff. By the time the older ones need me, the younger ones are off playing. It's working very well here!