Is the tiredness from Cymbalta ever going to go away?

I am day 21 and I am still so sleepy. I really wanted this med to work for me. My muscle tension feels better but I am still crabby and sleepy. I am working and all, but I don't feel like doing much else. I am so afraid I am going to gain weight from being inactive. Should I give it awhile longer? I am at 60 mgs.