The symbol is the symbol for "no notifications" meaning that at some point you've turned off the notifications on your phone (probably by accident in all honest). To do this you'll have likely pulled down the menu (see the pictures below) and turned off the notifications.

To get rid of the "i" and turn your notifications back on you need to again pull the menu bar down and click on the "Notification" icon. After pressing this icon, you'll see it light up and your notifications will return to the bar.