Very frustrated.. I have a iPhones 6s,64gb and some things seem to be gong wrong.. The home button won't work if clicked once . I have to double tap it to exit apps, and occasionally this won't even work. I cannot use the 'scroll down' or ' scroll up' notification & torch, calculator etc. I don't know where to begin on fixing this.. I bought the phone directly from my local Apple Store around 2 months ago, do I still have warranty ?