I also am a person who's just always tired. I presume it is because of my life-long depression & anxiety. Running continuously on one's nerves is tiring. For the past 2+ years, I've been on the maximum recommended dosage of either Cymbalta, or it's generic equivalent. (I'm currently tapering off due to cost considerations.) But being on the maximum recommended dosage of this SNRI has only added to my ongoing tiredness.