Yet another person who can relate to this here.
I am unemployed and spend all day by myself. There's so much I could be doing yet this lethargy bogs me down.
Here's the problem though: since I graduated 7 years ago and have been out of work, I've tried to engage in various hobbies that I feel may be useful/interesting/diverting, everything from teaching myself PHP to learning to create my own digital instruments. I'll be going okay with one thing but all the while in my mind something is going "you've been neglecting x, you should really be doing that", so I move to x and my mind is "you've been neglecting y, do that", so I move onto y. Eventually I end up spending 15 minutes here, 20 minutes there and not achieving anything.
Then I'll suddenly stop, just totally stop what I'm doing and stim for a bit, all the while my mind is trying to latch onto something I can get my teeth into, but the choices paralyze my mind.
So either I'm doing something and not getting anywhere, or doing nothing and not getting anywhere. I can't win!
Some days I can be busy but after several hours have absolutely nothing to show for it.
It really is most frustrating because there's so much I want to do, things I know I can do and would really enjoy if only I could spend more than 20 minutes on it at a time.
There have been points where I drink alot of water, that goes some way to easing the fug of lethargy, though not enough to help me concentrate.
I will have to try the diet thing, more greens, less biscuits. I know it's not a miracle cure-all but it's well worth a go, especially since I so want to, say, finish a piece of music. Hah, I have started working on so many pieces of music, pictures, web pages, and other projects, I have gigabytes of unfinished stuff here! I just want to lose the lethargy!
It's most frustrating though when you know what you want to do, you have your hobbies and interests, but for whatever reason you just can't stick with it.