Well, about the symptom / disease thing, here's what wikipedia says: <link>
"While it is normal for people to procrastinate to some degree, it becomes a problem when it impedes normal functioning. Chronic procrastination may be a sign of an underlying psychological or physiological disorder."
And they also say that even normal procrastination can "result in stress, a sense of guilt, the loss of personal productivity, the creation of crisis and the disapproval of others for not fulfilling one's responsibilities or commitments. These combined feelings can promote further procrastination." They also have a section on "Student Procrastination" you might be interested in.
But again, we may still be talking about two different kinds of procrastination. I do think worrying about it makes it worse - but it's pointless to tell someone not to worry about something... it's like saying "don't think of a cat."
meow
If I were you, I'd look for some ways to relieve stress. I get the sense that you're putting a lot of pressure on yourself, as though grad school and "a-life-worth-living" and everything else were at stake with every paper and every assignment. And since that's way too much pressure for mere mortals to face, you put off facing it by putzing around the computer instead of doing the work. Maybe procrastination is just one of many mechanisms through which your "avoidance" of this pressure is expressed?
I would suggest looking at things one assignment and one shower at a time. I'd also suggest taking a calming solitary walk before starting on a project, and then taking your homework to a very secluded, distraction-free (read: internet-free / computer-free if possible) environment. When I was in school I'd banish myself into a desolate corner of the library and I found I could really focus on things so long as there was nothing else to do.
Blech, not that you asked or anything. But I felt compelled to put that all out there. Probably you should talk to a guidance counselor at your school instead of listening to me. I am not a therapist, and I still haven't gotten Slate blocked yet.