Wilburforce - 12:49 pm on Oct 12, 2012 (gmt 0)

the serps for my sites seem OK but no hits

So either people are finding but not selecting your sites or

WMT reports a huge drop in search termes

there are less searches for those terms on Google.

IF - someone searches for a term on Google
AND - your site is well-placed in the results

THEN - lack of traffic cannot be attributed to Google.