Keep the faith Roger,.. it'll come right.
With the economic slowdown it is harder to pick up custies than it was this time last year,.. and the other cleaners near you who pick up work without canvassing probably have a customer base containing more young professionals and family's with kids,.. the kind of custie that networks and recommends a lot more than your older customer base might.
The only thing to do is learn and adapt. Diversify, canvass (Or pay someone to do it for you,.. commission only, and payment after you get paid of course!), maybe a small ad in the local rag. ( B&W text only seems to work well for window cleaning ads!),.. persevere through the hard times,.. even at its worst cleaning windows beats an office job!