lol, first, have u charged it up? cause if its running out of battery, of course its shutting down by itself...

Next, I dont know whats the condition of "bricked" but i guess its when your phone wont turn on, that means bricked so probably you would want to look through posts regarding "bricked". Im new here too and i spend 7 hours in this forum to have a crash course of the beginning level xD. you should do that too.