Turned off "Spider Sessions" -- and hurt my ranking?

[fightnever777]

There is a facility from my backend to switch off the spider sessions (however this does not prevent spiders but just stops them starting sessions as a customer would and prevents items being added to cart by the spider). I was also aware that a spider session is a high security risk.

After I switch off the session my site was effected in google.com. My keywords are no more ranking in google search engine. But it is ranking in google.co.uk and yahoo.com and msn.com. My site is not displayed in allinanchor tag which really surprise me. I have again switch on the facility which has been provided but still no results are comming up. So guys please help me out. How to get back in google?