What's the secret?

Today I worked an eight hour day. Which, for most of the world, is just a normal day at work. But not for me. When I work at the school or nanny, it's usually four or five hours at a time (even though it often feels like ten hours!). But today I had to be at work at 7:30 in the morning. Which means I needed to leave my house around 7. That would have meant having Harrison get up on his own, get ready, remember to let the dogs out, and lock the house up while getting to his bus on time. Me, of little faith, decided this was too much of a risk at this stage of the game, and had him sleep over at his dad's so his morning routine would be supervised. I worked my job, then arrived home just a bit after both Arlie and Harrison. I was pretty tired - not that I'd worked hard - but mostly because there wasn't much for me to do so I spent a lot of time finding things to do or twiddling my thumbs. And when I'm bored,  I get tired! (I did enjoy the job a lot though!). Still, I could have easily fallen asleep for a little nap when I got home but instead I........supervised chores, made dinner, had an unexpected guest for dinner, met Jeff coming through the door with a migraine (his are scary and stroke-like so I spent some time debating and ER visit), took Harrison  and Arlie to Starbucks (payback for an earlier day where they did their sisters' chores), made lunches, cleaned up dishes and kitchen, and THEN I had to work on volunteer stuff for the book fair at school. Now it's 11 p.m. and  I'm so tired and I wonder - what is the secret? How do moms who work full time balance their time and fit everything in? Forget about working out - I was booked up all day and way too tired at the end of the day to do anything about my physical fitness. I just can't help but wonder - what "gives"? Obviously no one can do it all, so what things do working mothers skip in order to find time for other priorities? I'm lucky in that I do not work full time so I cannot speak to how to balance a family while working full time. But on days like today when I'm working all day I think about working moms and wonder how they do it all. How do they spend quality time with their kids, find time for fitness, cooking, cleaning, volunteering, and everything else? It just seems like a depressing cycle of being too busy, too rushed, too tired and never enough time. I already feel that way sometimes and I'm not adding in a full time work schedule to the mix. Working moms with families, tell me your secrets!