sounds like you maybe in early labour, unless your baby is in the poisterior position you should feel most of yur contractions in the front of your tummy, you should start timing them and depending on your hospital, and when they like you to come in, let them know whats going on :)
Its possible that maybe you are having contractions, but you could also be dehydrated...which cause those symptoms, but you should always call your OB/GYN office to speak to a nurse.