What is this awful pain?

[Shauna Due Nov. 9th]

Im 31 weeks tomorrow. I woke up this morning feeling like I had been hit by a Mack truck. My abdomen was so sore that I could hardly breathe and sitting was out of the question just because it was so uncomfortable. I had an ultrasound last Thursday and at that time, my baby boy was in frank breech position with his hands covering his face. I knew from the movements and kicks that I was feeling that he was no longer in this position so I figured that he had flip flopped while I was sleeping and made it it a point to punch everything he could while he did it (lol). The pain has gotten worse and worse all evening. Now my belly is so tight (rock hard to the touch) that I cant even hardly stand up straight. It isnt the top of my abdomen so I dont think it is contractions. It is more around the area of my belly button to my hips.
What the heck is this pain and what can I do to relieve it??