like everyone has said it sounds like the early stages of labour, i lost the plug at 3am and had period like discomfort tried to sleep but couldn't, phoned hospital and they told be if it gets worse, once i can't talk through them i could go up the hospital. Whilst it may feel constant is it peeking at times (like more painful sometimes then eases but is still there) if so start writing down the times this peak happens and see if its regularily.

If you want to get things moving then lunges or a gentle walk are always good. but if you want to slow it down/stop and ease the pain have a nice bath and get the body to relax and try and get some rest because even if the pain stops now, chances are it'll be back soon!