Ah yes I've had two of my labours start like this. At the time it is very uncomfortable and frustrating but as Danielle said it is terrific for getting your body ready for when labour starts properly.

I was only in full on labour with Angus for 2 hours before he was born and Caleb for 90mins. I'd much rather have all the pre labour for days and have the last bit all over that quickly than no prelabour and a 9 hour labour anyday