Someone Stole my phone and is using Facebook messenger on it, is there a way to track it?

Block the phone through your cell phone provider and cancel tand disable your account and tell the provider why.

That'll fix the thief.

You might want to ask your provider if there is a way to track where the phone is.

If its an Android device and you are logged into Google Play

https://www.google.com/android/devicemanager

Apple

http://www.apple.com/icloud/find-my-iphone.html

All you'll get through Facebook is the IP, and that is no use. You can however log out of all sessions if you request a password change, or, go in the settings on the desktop version of Facebook, go in security (I think) and find the devices you are currently logged into.

if you have your GPS Location activated on your phone.

call the cops to track it.