I have had unproductive patches too as an independent. right now I am going through a reasonably productive time. There are times when the inspiration just kind of flows, and even hard problems end up being easy when confronted. There are other times when simple problems end up hard. There is some natural oscillation between the two. I have started to learn to take advantage of the pattern. Take down time when I need it (that's a hard thing to do as an independent) and work hard a lot of the rest of the time, even if it's only 6 hrs a day of hard programming (and probably 4 hours a day of other crap, and another 2 hours a day of still other stuff).