Janie, I had lots of period type pains for quite a few weeks before I finally went into labour with DD2. I honestly didn't really know if it was prelabour but I suppose in hindsight it must have been. But when contractions started there was no doubt in my mind about the difference LOL

It could well be nothing to worry about, but like Beata says I'd ring your ob or the hospy if you are worried At least bub is moving for you heaps that's always reassuring