firefox randomly logged me out of everything.

You mean logged into other websites not Mozilla accounts? Is gmail a specific set of accounts or that is where all the accounts you refer to are? I'm surprised you may not have a copy of the accounts or is it there are so many you hope Fx can restore them rather than enter them manually again? If you are talking about cookies or passwords what have you done to understand how they may be backed up and restored etc. like even use a Primary password to better secure login details.