Work anxiety

This week was an unusually slow week at work.

I didn't raise my hand to get more work. I decided to try to clean off my desk and deal with some nagging assignments. But a not-so-unexpected thing happened. I was totally unproductive. When I thought about doing that lingering work, I would panic and start surfing the web. And then I thought, crap, I wasted all that time, and I'm getting later and later at doing this work, and then I would feel even more anxious and still wouldn't do the work. That night I had trouble sleeping. Finally, at the end of the week, I managed to tackle the work, only to realize that I didn't have time to finish and if I had used all that time I wasted it would be done by now, and this will reflect badly on me and affect my reputation, all of which makes me feel even more anxious. Like pit in my stomach, heart beating faster anxious. And of course, I feel terrible that I'm taking time away from my family when I'm not even accomplishing the work I'm supposed to be doing.

It sounds ridiculous, but it feels paralyzing.

I've tried various productivity tweaks, including uninstalling my web browser of choice (because that's usually how I procrastinate), installing LeechBlock, which stops me from browsing, making to-do lists before I leave, restructuring my work day, etc... nothing seems to help.

What say you, Internet friends? Is this normal and I should just get over it? Is this an extreme version of normal unproductivity and procrastination? Is the solution just to be more busy? Is there some magical productivity hack I should be doing to change my habits? Do I need therapy?