L.B.
I am 46 with a 15 year old - I have always been a single working Mom.
What I have learned to do is to cook on weekends - things that can be re-heated and served during the week, or "re-invented" into other, quick meals. A pot of red beans, spaghetti sauce, a roasted chicken, casseroles, etc. During the week just add a quick veggie, and viola dinner is served.
I don't sweat the little things - mail on the kitchen table? Eh, I'll glance through it, throw away the junk and sort the important things. Laundry - I do on and off during the week - throw a load in the wash in the morning and dry it when I get home in the evening.
I try and run small errands on the way home or on lunch time...but, honestly, I usually just do them on the weekends. I find when I put off needing something on, say a Tuesday, by the time weekend rolls around I realize that it was more of an impulse desire and I usually don't need it after all. Saves me money :)
I decided years ago when my son was little that I would rather come home and enjoy time with him rather than scrub walls and polish floors. Our house is a little cluttered - not everything is in its place - but for the past 15 years of parenting I have managed to spend more time with him than with the mop - to me, that is more important than a perfect house.
Don't sweat the little things K. - if the dishes don't get done right away - just rinse them and let soak in the sink overnight, towels, sheets, and sweat pants can be thrown in the washing machine in the morning and dried when you get home - it is okay if they stay in the clean hamper for an evening or two until you put them away.
Look for little ways to reduce the pressure you feel from getting it all every night - in the long run, no one is going to suffer from a frozen pizza and a pile of mail on the table.
Good Luck
God Bless