This makes it very hard to concentrate on code. I'm nominally functional for anything that doesn't require significant cortical activity. And no, phrases like 'nominally functional' and 'significant cortical activity' don't.
At work I've been focusing on the hard parts of the project, so I could put off the REALLY hard parts. I've run out of hard parts to work on, for the moment. I can't do the rest of them until I do the really hard one.
I haven't actually managed to do anything significant on it yet, due to the afore-mentioned headache.
This frustrates me.