A possibility is that thunderbird had a problem with profile and created a new one. That is, your profile may still be in your profile folder. I cannot give explicit steps for browsing files in Linux, but thunderbird may help. Try this:

1. click help>troubleshootinginformation
2. scroll down to 'profiles' and click 'about:profiles'
3. you are now looking at listing of known profiles, is one of them your old profile? if so, launch it. if not,
   • click 'open profile' of one of them (this places you in the LInux file view)
   • exit thunderbird
   • back up one folder so that you see all contents of profile folder and can view contents of each
   • look for known files, such as abook.sqlite, which is the addressbook to help you identify your data
   • if you locate your addressbook, look also in the Mail and Mail\Local Folders folds for your message files
   • if you find them, you can copy them to the Mail\Local Folders folder of the active profile

Hi david many thanks have now retrieved all my old email so this was a great fix no luck with address book but at least you fixed this for me as i was lost as what to do so many thanks of this. Am new to using forms as you may have guest so many thanks

You are welcome. I was glad to assist. Your addressbook may still be there, as thunderbird would have no reason to delete it - but you at least now have your mail.