I’ve been underwhelmed, underexposed, underutilized and under fire. I’ve been calm, tranquil, serene, at peace, catatonic and dead drunk. But never underwrought. What does it feel like?
I think we’ll have to extrapolate, as I didn’t find the word “underwrought” at www.m-w.com. Its presumed antonym “overwrought” is the past participle of “overworked”, most likely in the sense of overworked metal. That is, it refers to a stress-induced condition of fatigue and brittleness, similar to metal fatigue.
Thus, “underwrought” could be interpreted as “underworked”. Depending on how you used it, it could just mean that you were bored (with no work to do), or it could mean that your workload is light enough to allow some flexibility. It might even mean that you lack sufficient training or preparation for something (similar to “untempered”). If you were inadequately trained for a job, and it stressed you to the breaking point, you might manage to be underwrought and overwrought at the same time. 
“Overwrought” also meaning excessively agitated, upset, virtutually a nervous wreck over some kind of stress – perhaps “underwrought” is that state brought on by relaxation and meditation, controlling wayward emotions until you really don’t give a hoot?
Had a couple of experiences like that while drunk out of my mind in the past. Trouble is, “underwrought” always switches back to the other side of the gauge when morning comes and the headaches begin.
Ironic, ain’t it?