Can chronic pain be cause someone to lose their appetite, feel depress, and start losing sleep?

Yes: And if taking medication, would not be unique for analgesics to cause all of the above. See current doctor and have a full conference about all of these issues. Meds can be modified and varied, and the whole situation can be improved.

Yes: Absolutely. If you are on pain meds, this can make mood issues worse as well. Might be a good idea to see a pain psychologist to help with coping mechanisms and how to best deal with your pain.