Gmail is one of the widely use email service.There are lot of features in gmail. There is a security feature for gmail known as remote logout. Many of use more than one computers to login to gmail account. Some times we often leave the browser opened & not being logged out of gmail or we are in cyber cafe and any power cut or computer faliure occurs and if the computer is at office or any public place your account may be hacked or misused by someone else.
But there is a method by which you can log out from your gmail account remotely.
Open you gmail account and go to bottom of the page ,there you will see something as shown below..

Now you can click on “Details” which shows you a pop-up having details about your last sessions.Click on “Sign out all other sessions” to sign out of gmail at all other places exept the current.
By this simple feature you can check that your gmail account is hacked or not.