Insomnia is common in mild depression and anxiety disorders. In such cases if it has been chronic treating both the conditions probably is beneficial, however, the main focus should be in treating the mild depression and/or anxiety. You seem to be on one antidepressant. There are several other antidepressants/anti anxiety medications, which may benefit. If a single medication is not helpful we often use 2 medications/combination strategy to treat. I suggest that you see another psychiatrist for a second opinion in this regard.