About 1 month ago I changed my website to https links then I found I got less and less traffic when I check via Piwik. However, the data in my Google Webmaster Tool seems to be the same with before. So here is my questions: 1. Why does the traffic lost happen? 2. What's the difference between the 2 tracking tools? 3. Which one should I believe? 4. Should I do anything to stop traffic lost (if there is any) or change back to http? Thank you for your replies!