Hard stomach at work

filxoxo

I'm on my feet for my whole shift at work. And although it is short (5-6 hours) I'm starting to realize that my entire stomach is getting hard after the first couple hours. I brought this up with someone and they mentioned contractions (which I went to the hospital before for something unrelated and they told me I was having contractions that I wasn't even feeling.) But as far as I know, the hardness isn't coming and going. It's difficult to tell because I'm multitasking and don't really have the time to focus on what's going on with my tummy when I'm running around.

After I sit down or rest my stomach loosens up and LO shifts around and everything seems to be fine. But does anyone know why that happens/has that happen to them?