I once worked with a young woman that had a very traumatic childhood. She had been sexually abused by her brother and teacher, emotionally abused by her mother and physically abused by her father. When I met her she was a very unhappy person with low self esteem, severe depression and anxiety and at times she was self harming and suicidal.
If you are feeling down or depressed on a regular basis there is no substitute for talking it through with a qualified professional. However there are certainly some tips that I can give you to help you cope with those feelings that may get you through a particularly tough day.