do puppies usually go through a "rebellious" stage a bit like teenagers?
my pup has become quite naughty these last few weeks, her housetraining seems to have suffered a set-back and she is nipping and barking a lot, Im not sure whats causing this could it be her age? she is 14 weeks on Monday

Teenagers?  Very much so ;)  Stick with it, be consistent and you'll both come out the other side.  Bear in mind that many of these behaviours can also be exhibited to relieve teething pain, and 14 weeks would be about the start of your pup loosing her milk teeth, so make sure she has plenty of ways of chewing and releiving the discomfort - some people apply Bongela to the gums, and find the 'naughtiness' also disapears......