Feet hurting already?

Lynzee • Mommy to Ammarie, born on March 3,2016!
I'm only 18 weeks, and have only gained maybe 5 pounds. 
I've always been petite, weight 109 at the beginning of my pregnancy. 
My feet are already killing me! The past few days, I've been running errands with my husband and after a couple hours, I just can't keep going anymore... I feel like this is way too early for foot pain! 
I guess I just want to know when other ladies began to feel it? 
Also, my back and hips are really sore all the time. That's normal, too,  I know.. I just feel like it's too early and I haven't gained enough weight to be able to feel all of this lol :)