What Causes Depression And Anxiety While On Cymbalta For Nerve Pain?

I have been taking 60 mg Cymbalta for about a year now for nerved pain in my back, neck, hip, and ankles... I was taken off of my Prozac for depression when I started the Cymbalta. My depression and anxiety have increased, while the nerve pain is still going on....I have also developed a sleep disorder in the past year where I go into such a deep sleep that it is almost impossible for my husband to wake me up.....When I do wake up, I have headaches and can t remember anything... I also am having trouble remembering names, events, directions, etc.......do you think it is the Cymbalta??????