Dehydration can cause severe cramps. I was in the hospital 3 weeks ago because I had been cramping for at least 10 hours. When they ran tests, they figured out I was dehydrated. When they gave me 2 bags of IV fluid the cramping stopped.
The cramping can be caused by contractions or it could also be because you are still dehydrated. Drink lots of water that is what my dr tells me.