Tummy pain

I've been having an achy sort of pain in my stomach for the past two-three hours. I'm 18 weeks. I've been drinking water and I tryed going to the bathroom and neither has helped at all I've also ate. The pain is starting from the bottom of my ribs all the way down to my hips all the way across. Has anyone else experienced this? I'm also a first time mommy and I worry very easily