Freelancer on sick leave

For the last two weeks I've been battling the flu. Not the swine flu or anything, but the regular, nasty kind. You know, the usual: fever, headache, feeling as if you'll cough out your lungs... I'm all better now, thank you.

My point isn't what type of flu I had. It's more the fact that during those two weeks I have written... nothing. Zilch, Zero, Nul. Exactly 0 words in two weeks. No progress on my short stories, nothing new on the bigger project. No research done, no articles published.

I basically disappeared from the face of the Earth and am still recovering and trying to wrap my head around all the things that didn't get done during my "sick leave".

And while I recover it's unlikely I'll start writing with the previous speed right away. To be perfectly honest it's unlikely I'll write anything before February starts. And that means that the only money I earned was at the very beginning of the month and whatever passive income I made off of Helium and AssociatedContent.

Which, in turn, made me wonder, how would it all look like if I didn't have the full time job and income from that to fall on. It made me wonder about all those deadlines I would have to meet despite the high fever that made thinking seem like a superhuman ability. The image that appeared in my mind was quite scary, to be honest.

I don't get seriously ill too often. It's basically once a year, twice if I'm really stressed and tired. So it's between two and four weeks out of the entire year when I wouldn't be able to earn any money, not counting the passive income. Not factoring in the fact that I would work a lot more with actual clients, if I was pursuing the freelance career full-time, it means that four weeks in a year I would risk deadlines, disappointed clients and any future income they could've bring me.

All this paints a rather depressing image of what could happen to me and my career if I dare to have a flu while working fulltime as a freelancer. It does not encurage me in any way to quit my office job and switch completely to freelancing.

Are there ways to ensure that if you get sick your career won't fall into pieces? What failsafes one can instal into the business model to give oneself time to recover?

Anyone?