. Were do you live? I ask you this because in some parts it getting cold and he/she could be trying to hibernate but I dont know if that is the reason because it sounds to young want to do this.
it could also be the things it is seeing out side the cage or the things its hearing. try putting it in a quiet place and take the cover off. and don't force feed it unless it is a must. this can cause a lot of stress

jake