Someone has hacked my Facebook account?

[Saman]

If your Facebook account is hacked, then who ever hacked it must have hacked your email too. One way to hack a Facebook account is to hack they're email account. Usually a person who knows you and won't find it any difficult guess the security question to reset your password for your email account or just guessed your password. Then went to your Facebook and resetted the Facebook password. If you can still access your email, then change your security question to a harder one and change your password. Go to your Facebook and forgot password option should send a email to your email and then reset from there.