Hello,
Your licensed features will revert to the free version if EAGLE has not been connected to the licensing system for 30 days (It used to be 14 days but assuming you are running a v9 version it'll be 30 days). If this is the case then all you need to do is tell EAGLE to reconnect to the licensing system and you should get your Premium entitlements back again. In the EAGLE control panel at the top right you'll see a drop down box. This will have three options:
1. Either "Go Online" or "Go Offline"
2. License Information
3. Either "Sign In" or "Sign Out"
If you are not signed in ("Sign In" will be the third option in the menu) then go ahead and sign in. It'll pop up a dialog for you to sign in using your Autodesk account (the one with your subscription associated with it).
If you are signed in already it may have gone offline ("Go Online will be the first option in the menu"). Choose the "Go Online" option from the menu and it should connect to the Autodesk license server and obtain a new license token.
Finally, if it's already showing as signed in and online then choose "Sign Out" and then once it has signed out the go and choose "Sign In" again which should force the refresh of the license token.
Best Regards,
Rachael