I found that the 2nd or 3rd week back at work were sort of a climax of "how the hell am I going to manage this?" Before we settled into a sort of rhythm...as best you can with a baby anyway lol. I went to bed towards the end of week 2 in tears because I was exhausted, the baby wasn't settling for my parents very well, the bigger one was struggling with me not being there every morning like I had been for almost a year, and the house was a health hazard because suddenly there felt like no time to do any housework.
I'm slightly different, as I don't work nights, but I do get up at 4.40am on work days. We've come to an agreement that I will make the sandwiches in an evening when I make tea, and I will put fruit in pots etc for the big one, but otherwise everything they need to be doing in a morning to get out of the house is none of my business. I work 20 miles away, and I can't have my phone with me. There's nothing I can do about it, so I just leave them to it.
Ive found having a clear split of who does what has massively helped. For example, the big one has a club on Saturday mornings, and we now take it in turns to get him ready and take him to that while the other one stays with baby Biscuit, gets her breakfast, gets her dressed, and has her down for her nap by the time the other one gets home.
School-wise, homework is done on Friday evenings, and we have set days that we do his reading book, and these are things I do. Mr Biscuit washes the pots in an evening, puts the bins out, and does the uniform ironing on a Sunday afternoon while I supervise shower time. He also takes and collects the big one from his Thursday evening club.
I usually work Tuesday, Wednesday, Thursday, then I set Monday aside for boring stuff like food shopping, and Friday is my day to do something fun with baby Biscuit.
I make lists too. I always have a list of stuff that needs doing ASAP and a list of "big" jobs that need doing but are less urgent, and I try to do one big job each week. So this week I'll be defrosting the freezer. It's not life or death but it needs doing, and ticking it off makes me feel like I've achieved something.
It's all a bit military, but it works for us in general, and it leaves us the weekends free to do nice things together if we want.