Help?

I will be 40 weeks on Monday. I was checked last Tuesday and was 2 centimeters dilated and 50%effaced. Today (I believe) I started losing my mucus plug. But I am having HORRIBLE pains. I can't tell what they are. They are too constant to time. They are happening back to back but don't last long. I'm really bad at describing pain but just curious if this sounds familiar to anyone?