First, you should check if you have been penalised by Google.
- Perform a crawl on your site and take note of the number of indexed pages
- Check this number up against Google's search - "site:yourdomainname.com"
- Search "link:yourdomainname.com"
- If nothing comes up or the numbers are significantly lower in Google then it is likely you have been penalised.
You can ask for reconsideration to Google and your site will lose the penalisation if successful.
Instructions are here: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=35843
As for the 0 seconds time spent - it may be because of the current spammy link profile. People (or bots) may be clicking through to the site and immediately leaving.