Hi Maries,
Oooh sounds exciting! If it is real labour pain, it will not get better over time...it will steadily get longer, stronger and closer together.
With both my previous ones it started out feeling like an upset stomach, that you feel you need to go spend some time on the loo. Then it gets to a point where it feels like someone is trying to break your lower back and the uterus muscles contracts so hard, it feels like it is going to tear open any moment. (sorry this sounds really bad, but that's the way it really felt, don't want to sound scary) But then I suppose, you should not be waiting for the pain to get to that point....seeing as it is a vbac.
How far are you from the hospital? Better safe than sorry I would say, rather go and just let them double check. I'm booked at a Netcare hospital and then you can just go to the maternity ward if you have any concerns, they will check for free and if needed call the gyne. I stay 4km from the hospital so they know me fairly well by now.....I just pop in for any questions.
Good luck...keep us posted!!!