My iPhone 6 won't turn on!

My iPhone 6 is not even 6 months old and it was at about 50% when suddenly the screen went blank and wouldn't turn off or on no matter how many times I pressed/held down the power button. It has been charging for over an hour now and still no results. Resetting it through iTunes on my PC is a last resort because I have not backed it up to iTunes yet and if I plug it in to iTunes it will have me set it up as a new iPhone, which I don't want. What should I do?

Thanks!