Either the battery has lived its life and need to be replaced or it is not fully charged. Just try to use it completely. Then, shut off for couple of hours. Then, use the camera again to discharge it fully. Last, charge the battery fully and see if that helps. If not, then change the battery.
If you're using the EN-L1 battery, they have a history of becoming unusable after a few months of heavy use OR 12-18 months of limited use.