Maybe it's just all happening really slowly, some women dilate slowly over days and don't even realise properly, then they have quite a quick efficient birth when it's all finally happening! (mine was 11hrs established labour from wed midnight to thursday morning, but as I said, had been achy and having on and off contractions from monday)
I remember feeling so fed up though, poor you!! Think of it this way: no matter what happens you will have your baby in the next two weeks!
If you're worried about the way you're feeling though, do ask your mw, thats what they're there for.