I also stress myself out on top of a stressful job.
I know there was another thread that touched on this somewhere, but I'm not sure where...
But stress itself can become addictive, too. The adrenaline rush and endorphin release that happens when you push yourself to the edge with a project can be similar to the "runner's high" that marathon runners get. PLUS, if you do a good job on a project, you get the accolations of coworkers, and possible a boss. Pretty heady stuff.
So it is tempting to stay in those stressful situations because the gains
seem so great. But the toll that it is taking on you mentally and physically in the meantime is quite high.