2003 dodge ram

i have a 2003 dodge ram 1500 5.7 hemi 4x4. so i was on my way to work today and my truck just turned off i mean nothing worked not even my flashers but there was a little red dot flashing. when i put my key back in the flashing stoped but stell nothing no flasahers and headlights nothing.is this just my battery or is it my security system. i am not vary mechanicaly in clined so any help be helpful.