I just got this S4 as an early birthday gift last month and the screen is randomly acting up. When I try to type something like 'lol' instead of 'lol' i get 'lfidkfjddiifoffjfdkfjl' random letters. and when I enter my password in, it friggin goes everywhere. WHAT IS WRONG? I havent downloaded anything and I even have one of those safety checkers tmobile give you on your cell phone. HELP ME