every where, every day, m seeing your accounts goes to "hack". some one is accessing your account from miles.
but you can secure your account, just you have to do some steps in your account setting and you can get notification on your mobile and on your registered mail.
1-just click on account(right side of your profile and click on " account setting".
2- click on account setting
and save all information according pic.
after that, whenever any one will accessing your facebook account you will get notification who is using your account and from where?
one more thing you can also select some some security questions and privacy setting .
also you can save some privacy with custom setting.