What is happening with my little white finch?

my little white finch is not moving , chirping and playing , she/he (read beak) was the most adorable and jolly bird i ever had always playing , chirping , eating , bathing BUT from last 2 days she/he became so silent and looks serious. now she/he is hiding herself /himself somewhere in the corner of room. she/he is only sitting on the floor, looks scared and numb.