I have the same problem, and while I don't know of any way to 'kill' it, I have found it a bit easier to work with it by having little two minute breakss after every major stepping stone in a drawing. Finished with the lineart that took me an hour to do? Two minute break. Got done with the coloring and shading of that intricate corset/belt/dress/etc.? Two minute break doing something else. Not only does it help you get back on track once your finished with the break, but the intervals in between allow your mind to temporarily focus on something else long enough for what your drawing to become boring or tedious.
