Sounds like the exact same thing I am experiencing, it could be post traumatic stress disorder, I have seen some terrible things which I just can't talk about but understand it has caused me some problems especially whilst i am asleep, eating healthy and no alcohol and excercise usually helps. But in your case, when you have no choice of what you eat or do, just try and get to the bottom of an event or events that may be eating you up inside and try work through them in your mind.