Trichotillomania. Is the name for a disorder where hair is compulsively pulled out or cut to the point it is destructive and conscious effort to limit it isn't successful. Stress certainly can percipitate such activity. That includes new stress of short duration and long term stress that may not be readily identified. Serotonergic antidepressants such as Prozac (fluoxetine) are quite successful as treatment.
Trichotillomania. This can be a serious chronic condition which is difficult to solve on your own. Check out trich.Org for many resources and tips, but often you need professional help.