Wow, you have lots of great advice that I agree with. I am a single mom of a 15 month old and I work full time too. I get you about being tired.
I totally agree with the "screw the housework" theory. I am naturally a clean person, but oh well, these years don't last forever. When my daughter is awake, I play with her, spend time, etc. Since she is getting older, I let her "help" me with little things (laundry, cleaning the counter, etc) which is actually more work than doing it myself, but it's spending time together, so who cares?
When she is asleep, I do things I can't do when she is awake. I take out the chemicals to clean the bathroom, I get on the email (like now) I do some yoga (I highly recommend some sort of gentle stretching, it works wonders, even 15 min!), and yes, sometimes I just lay down with her and rest.
I have readjusted my thinking on meals~ simple, healthly, small. 1 course is enough, there are healthy frozen options and Sundays are great days to make and freeze. Dinner now might be an avocado & tom sandwich on W/W bread instead of pasta salad, or an organic frozen burrito with added steamed squash and tom. Each takes less than 5 min and I don't care if my daughter takes some it, it's healthy!
These years are so short (even though some days seem looooong) and one day we will wonder where all the time went. I look at my mom's very clean house and am jealous, until I see her with my daughter and realize she would rather have a hectic, messy house and a baby than a clean house.
When I started this journey one of my friends told me "you will be tired all the time and pretending like you're not. It doesn't last forever, you just get through it. Drink coffee and laugh a lot" If the baby is happy, healthy, fed, clean, what else in world even matters?
Good luck!