A gigantic cluster fuck... but not in a military sense.

A huge fuck-up of epic proportions of some sort or another and its ensuing calamity. As in, the person or normal situation you were supposed to be a part of is now so totally screwed up as to turn the entire scenario into a farce; or something that could end up in you going to either jail or losing your profession.

A course of action that would appear to lead to a good outcome, but when undertaken, leads to a situation that is utterly out of control beyond human comprehension.

A shitstorm refers not to one bad thing happening, but to many bad things happening in a short period of time. Usually describes many unlucky, sad or just awful events pertinent to the person speaking.

A seemingly endless series of unlucky events, or negative occurrences.

when all the shit hits you at once. A whole bunch of criticism, or problems all at once. when in the shit storm you are being shit hammered.

A situation where oneself or something of value to self becomes attacked by a large quantity of basically crap, which must be fended off at a high rate in order to return the system to normal.

A monumentally disastrous outcome or event that nobody wants over their head. Usually caused by an overwhelming amount of smaller negative events(called crap) occurring at the same time hence the term "SHITstorm".