Here's a simple way to see if there is someone messing with your Facebook account.
There are several different ways hackers use a breached Facebook account. Automatic logins through Facebook allow hackers access to many different site accounts once they've taken over your Facebook. Spammers also hack Facebook accounts to gain access to your following. From your profile, a hacker can additionally gather a lot of personal information about you that can be used to steal your identity.
How to check if you've been hacked
If you worry that your account has been hacked, there is a simple way to check. Go to the arrow in the upper right-hand corner of your Facebook page and click on it. In the menu, select Settings. A new menu will pop up. Choose Security and then Where You're Logged In.
A list of all of the devices that you've logged into and their locations will pop up. If there is a login you don't recognize, chances are you may have been hacked. If you see anything that isn't you, click End Activity on the right side of the log to end the session. The hacker will be logged out, temporarily.