The first thing you should do when you suspect your Facebook account has been hacked is to **secure your account**. Try to log in and change your password immediately. If you can’t access your account, use the **“Forgotten Password”** option to reset it through your registered email or phone number. This will help you regain control. 

Once you're logged in, review your account for any unauthorized changes, such as altered personal information, unfamiliar devices, or suspicious activity like posts or messages sent without your consent. If necessary, **log out of all devices** from the account settings to ensure no one else has access. 

Next, visit Facebook's **Help Center** and use their **Account Recovery Tool** to report the hack and follow the steps to verify your identity. 

Finally, **notify your contacts** to warn them of potential phishing attempts or malicious messages coming from your compromised account. Implement **two-factor authentication (2FA)** for added security moving forward.