Mummy Mel this also happened to me although mine did stop after a few days. I also had some lower back aches (nothing a hot water bottle couldnt fix) and by the time i had reached term my GP said I was already 3cm dialated.
It all took time but i found that my body was going through the 1st stage of labour very slowly (over a week) so it could be a while...But keep the fluids up!

Good luck

Ann