Flooding - Becoming Overwhelmed After Brain Injury

I've never heard of the term "flooding" for mental overload, but this is precisely what I deal with multiple times a day when I warn the people around me that I am near my mental fatigue limit. I used to have nearly a half hour from the time I started noticing the mental shutdown until it made me unable to handle simple tasks, but that time has shortened considerably. Now I often feel the shut-down symptoms only moments before I "crash," which means if I'm driving a car, it's time to pull over, regardless of traffic or other considerations. If I can beat the "crash," and get some rest before it overtakes me, I can be "good" again in ten minutes; but once I crash, it can take hours to recuperate.