I have a site that was earning me lots of $'s a month using organic traffic, for the last 3 days i havent made anything at all.

I have checked and on the 6th August Google Bot visitied my site.
It still has the pages indexed but traffic has died.

Here are the stats for august and as you can see the traffic is getting lower and lower since 6th

01 Aug 2008 648
02 Aug 2008 701
03 Aug 2008 293
04 Aug 2008 427
05 Aug 2008 820
06 Aug 2008 803
07 Aug 2008 230
08 Aug 2008 54
09 Aug 2008 42

The site is a PR 4

Any ideas or advice please as this is my main money making site