I have this website I am optimizing since last june, originally it was an expiring domain with some PR and about 60 backlinks. I changed it to rank for many product names and reviews about them, however one week I built many links for it, and as you can see from analytics pic attached it got slapped by google, I want to know is this sandbox(even though it was old domain)? or penalty and what should I do now?
Deeply research on its on-page factors? Is there any low quality or scrap content or any other negative on-page factor?
about 20% of the page text content is something shared by all pages, so I used rewriter to make it unique!