Cramps! Arrrrghh!

I'm getting almost like period cramps really badly whenever I lay down. It really hurts, there's a lot of pressure, almost feels like I need to run to the toilet with a bad stomach. It happens every time I'm laying down. I know it's not labour or bh because it's not really coming and going. And it's not regular. I'm 38 weeks. Anyone else experiencing this? X