One week ago i get over 200 Unique Visitors a day from google but now nothing, just the visitors from my Backlinks. 5 days ago i ranked with 36 Keywords on a good position in serp tell me Google Webmaster Tools but 3 days ago there are just 12 Keywords and the serp rank is falling down extremly. My Website is 6 months old. When i look on Google Webmaster tools the hole month from my keywords, there are like 150 Keywords who rank in serp. What i should do?