Since I do not use Facebook myself, I am not sure if this would be any help...
But, if I understand your question correctly that your are missing all of your contacts from your phone, this might help to get them back.
If have synced your contacts on your phone with your Gmail account in the past, you should be able to go into the Settings Menu on your phone, go to Accounts & Sync, you should see your Gmail account. Tap your Gmail account, then tap the 'Sync Now' button, and your contacts should be re-synced to your phone.
"No matter where you go, there you are!"