Amen to what everyone else has said! With my first, I would get up and shower...and then get right back in bed. Nowadays, with more people to care for, I lay down whenever I possibly can. Sometimes I can nap and sometimes I just have too much on my mind, but I think I still benefit from just being off my feet. I used to get so annoyed when people would tell me, "rest up while you can, because once that baby comes there will be no rest for you!" But I'll admit they're right.
My LO is almost asleep in her crib so instead of running around like and picking up before my DH gets home, I'm going to lay down. The house isn't nearly as clean as I would like it to be, but it will all get done eventually. I think pregnancy is the only time I can let go of my I-have-to-be-productive-every-waking-second-attitude. Maybe because even when I'm laying down, I'm still being productive by building a human.
The overwhelming fatigue will let up eventually, and then it will be easier to get the house back in order. For now, let's all take a short break!