I think I suffer from this problem, I like to compare it to writers block or something like that, my problem is that I want to develop something but I don't know what and get frustrated at having a lack of ideas.
This frustration then gets interspersed with furious bouts of development on personal projects that can last 4-6 weeks, and then I go back to another 3 months of doing nothing and hitting my head against a brick wall.
This might seem counter-intuitive, but get a new hobby.
By which I mean, if your life as you're living it isn't providing itches that you need to scratch with software, a new hobby might provide some. Or, you might spot an unserved opportunity or market.
This frustration then gets interspersed with furious bouts of development on personal projects that can last 4-6 weeks, and then I go back to another 3 months of doing nothing and hitting my head against a brick wall.
Help?