I find that my focus is sometimes really strong, and then for apparently no reason it diverges to nothing, and suddenly I am writing a senseless entry on this site. I am really into the work I am doing, but then out of nowhere I can't focus and start looking around for things to do.
I think just stronger mental discipline will cure it, just force myself back to work and I will cause my interest to peak again, as soon as I see a neat problem or situation that I need to solve.
Diving back in!