Lower tummy/pelvic pain

I was at work today when I got a sharp heavy pain around my underwear line (pic below) it's not as bad when I'm sitting or even standing but it hurts a whole lot when I'm walking and it seems like the only thing that helps is to "pick up" my tummy. It hurts mainly in the front, I took some Tylenol and it helped with some of the front pain and got rid of the pain in my back. I'm a little over 30 weeks with my first child. Should I be worried? Has anyone else had this? If so, do you know what it is or how to make it better?