Sudden Visitor Drop [up 50%]: Google Update? How to Recover it?

Hey guys,
Did you experience a sudden visitor drop in your site's analytic stat?
Ranking for the keywords is almost unchanged. [At least by no way indicative of 53% visitor drop]
But visitors dropped 53% and earnings decreased to 70%! :(
What kinda update is this? And how are you handling it guys?
N.B:
1. My current meta description length is yet in old 160 characters.
2. Majority of my articles are product review type and the site is Amazon affiliate based.

Please share your experience,…

Sudden Visitor Drop [up 50%]: Google Update? How to Recover it?