Hi Veronica
I have also had the heavy feeling down in my pelvis after doing a bit of walking, and the period type cramps in my front and back, but like you I have no idea whether its pre-labour or not.
As for the Braxton hicks the only way I can tell that I am having one is because I feel my heartrate increase before my tummy goes hard.
Its exciting and confusing at the same time, everytime I feel something happening I think 'Is this the real deal or not?'.
Anyway not to long for us now...