Feel bad

feel bad , feel badly : Discriminate carefully between these terms. If you mean to express the idea that you are ailing in health, feel bad is correct. Feel bad is synonymous with feel ill and is correct. One might as well say feel illy as feel badly if the latter were correct as applied to health. However, feel badly is correct when the intention is to say that one's power of touch is defective as through a mishap to the fingers.