Ok first of all i feel like an idiot, was at the gas station drove away and heard a loud CLUNK. turns out i drove away with the hose in my tank still... ripped it right off..

anyway after that while driving at low speeds only, i hear this small clunk coming from the rear its intensity gets lower and speed of accurance gets slower equally making me believe its something floating around in liquid or something hanging from another object.
the strange thing is.. it only happens when my car is turned on, and when it is jerked in a front to back motion. no sounds come from side to side motions..
to check it id tap on the brakes, and there it is clunk...clunk............clunk
only when car is all the way on
what the hell is going on?!