31 weeks pregnant and weird oain

About 30 minutes ago I had a sharp stabbing pain in my side. I thought I twisted funny or something. It finally started to subside after 20 minutes, and now the entire front of my stomach hurts like a Charlie horse. Very bad pain. I don't think it's a contraction because it's not really subsiding much at all. Advice? I'm going to call my doctor if it doesn't go away when I lay down for about 15 minutes.