How did someone in a nother country I have never been to hack into my facebook acount?

[Hades]

They sent notifications for something like that too?

Hacking an account isn't that hard (I would know).
All they need is your email and password. Email is quiet easy to get, most people make it public these days.
As for password, you could have hinted him by mentioning simple yet important information like birthday, pets name, etc etc.. Or, they could use brute forcing, guessing your password by using softwares. And the last easy option would been keylogging.