Not sure if this is IBS... Sudden severe clear diarrhea, vertigo, syncope, hot flashes...

So every once in a while (used to be a year or more apart but now 2 or more times a year) I very suddenly get very ill. I get vertigo to the point I can't hold myself up on the toilette, rapid hot and cold flashes (think Christmas slow blinking lights), severe abdominal spasms (you can see my stomach jerking through my shirt and it feels like someone is trying to pull my intestines out), violent diarrhea that has almost no actual stool (looks like water and sounds like I'm spraying a hose full blast into the toilette), clammy skin, and sometimes I actually pass out. It's always very sudden. One minute I'm fine and the next... then just as suddenly as it started it stops and I'm left feeling like I was put through the wringer but otherwise fine. I have been diagnosed with IBS as well as about 13 other medical conditions. Recently I've was sent to a neurologist because of other symptoms, who found signs of a neurological problem (babinski reflex, hyperreflexia etc.). He seemed to think that all the problems I have are related somehow but he was stumped as to what could be the problem. Unfortunately he took a new position at another office and now I am back to square one and looking for another doctor. The only things we did establish is that there is something very wrong, it seems to be at least familial, and there is no physical damage. I was wondering if anyone had any ideas as to what is actually happening when I get like this (is it IBS and if so what exactly is happening or is it something else?) or what I should do the next time it happens.

This is not IBS. Like Anne Boleyn said: you need to find a good doctor who CAN diagnose you and actually help you. To me, after an episode like you had, you should have been hospitalized and put through a battery of tests...and that includes nuerological tests.
Wishing you all the best, and take care!