Here are some possible reasons for sudden traffic down
You may lost your back-links
Sudden Change in Search Intent
The Content on Your Page Changed
Copy content or Quality of your content
Your User Experience Has Diminished
Irrelevant back-links.
Do you have any list of powerful links? It might help!Add some quality links to grow your backlinks profile
Check your comments and link are they spammy ones..I made some forum, profile links and blog comments and I was getting good traffic till 9th October. Now, traffic is dropping daily. What to do?