Anyone else exhausted??

Caitlin • Married on Halloween 2015 👻, expecting our first baby Aug.17 2016!
So I've been pretty active through my pregnancy. I've gained more weight than I'd like, but it hasn't stopped me from going to the gym and running a few miles and lifting weights 3 times a week or so. But for the past few days, I am just wiped out! My husband and I took our dogs to a dog festival this morning, and afterwards I basically napped for 5 hours.... Anyone else experience this???