Stress seems to simultaneously prompt decision making while at the same time destroying ones ability to make a decent choice. Just leave the sketchbook sitting when you can't get to it. THe thread will be waiting. Besides, there's nothing wrong with drawing total crap during the busy times.
Anyhow, that guys face is great. You're always a reminder to me that I need to start thniking of faces more as a combination of planes.
Keep it up as best you can. End of semester times are always going to be ridiculous.