Hi, okay so I've had my nexus 4 since around July and I just around January it started turning off by itself every once in a while. it started then happening more and more recently and now it turns off whenever its not plugged. It basically only works when I have it charging. It's beyond frustrating and I have absolutely no idea what to do! Ive dropped it way more than a "few times" and the back is cracked but does this have to do with the frustrating fact that it doesn't work unless its plugged in? Also when its not plugged in, if I turn it on it will turn on and the farthest it'll get is to the "Google" logo in the beginning and then turn off and on and on again by itself constantly until it practically drains its own battery and doesn't re-turn on. PLEASE HELP! :'(