This is a serious issue, and you're right to be concerned. It sounds like you're dealing with a negative SEO attack. Here's a breakdown of what you can do:
1. Disavow Files:
You've already done this, which is great! Make sure your disavow file includes the domains that are redirecting to yours. It's crucial to submit this to Google Search Console.
Consider disavowing links to the spammy domains: This is a more aggressive approach, but if you believe these domains have a vast network of spammy links pointing to them, it might be worth disavowing those links as well to further distance yourself.
2. Monitor and Document:
Keep detailed records: Document the drop in rankings, the referring domains, and any other suspicious activity. This will be useful if you need to escalate the issue with Google.
Use Google Search Console: Monitor your backlink profile for any new suspicious links.
3. Report to Google:
While there's no guaranteed action, it's worth reporting this as a potential negative SEO attack. You can use the Google Search Console Help Community or the official Google Webmaster Twitter account to raise awareness.
4. Blocking Referrer Traffic:
This is a controversial tactic. While it might seem like a quick fix, it can sometimes backfire and even signal to Google that you're trying to hide something.
If you choose to block, do it cautiously and only as a temporary measure while you work on the disavow file and report the issue to Google.
5. Focus on Positive SEO:
Don't let this derail your efforts. Continue building high-quality content and earning legitimate backlinks. This will help your site recover faster.
Important Notes:
Google is getting better at recognizing and ignoring spammy links. However, these attacks can still cause temporary damage.
Be patient. It can take time for Google to process your disavow file and for your rankings to recover.
If your rankings don't improve after taking these steps, consider consulting with an experienced SEO professional who can provide more tailored advice.