Like Virgo sez,
And a bad week is nothing, if I have a bad month I worry a bit, but I'm not just going with one source of income, if CCBill craps out, or anyone else, I generally seem to make up for it somewhere else. If my traffic is steady it all usually works out.
Diversify, unfortunately this is the only biz I'm good at, so I diversify within the biz

Splitting your work between short-term and long-term projects makes a lot of sense as well.
As has been said here repeatedly, "Keep Building!"