After analysing many websites in few niches i realised that even complete whitehat, big authority websites drop after some time and lose search visibility so its all normal (in my opinion it seems that google just want it this way otherwise they would give too much power to few strongest websites and nobody else would have any chance). Now i dont even monitor or watch on these google updates anymore. Ok i might read some news, check my ranking but thats all. I only focus on content and new links.