First you should try to recover the account on your girlfriend's device, if it's a computer clean the cash and delete cookies. You'll have to wait 24 hours to log into your Facebook account. During this time, your account will still be visible to your friends on Facebook, but you won't be able to access it. This waiting period is an extra security precaution we set up to protect your account and the information in it.
None of the responses have worked for me - I have had the same problem Waited 24 hours and 96 hours as well. Have verified my identity, used new email, all the above. Facebook is worthless when trying to get help through their portal. Has anyone solved this issue yet?