I don't think IT is any more stressful than any other attention-filled, high demand position in the work field, I think what makes it stressful and piles on the anxiety is what everyone else in the world has to deal with any job: co-worker cooperation (or lack-there-of), difficult boss, tight deadlines, piss-poor-planning, busy streaks in industry or retail, demanding work performance, stupid end-users/consumers, ect. I could go on forever.
Almost every position I've applied for has asked "How do you deal with stress?" because it's something that comes along with any job, not just IT. If you don't have a particular outlet (e.g. break time to take a walk, co-worker to vent to, shruggable conscious, squeeze ball with your co-worker's face on it), then you better get one.
But let's face it, a lot of anxiety and stress can be self-inflicted, too. I've been a Systems Administrator by day profession for quite some time now and I couldn't think of a more fluid position to have to constantly get used to. Every year, I see ton's of "new guys" come in and can't handle it because they are cocky, their resume doesn't match their skillset (e.g. LIED) or just don't have common sense. If you know your job, do it well, can multi-task and prioritize without having someone hold your hand, everything else will fall into place.