Ok, so if your sleep problems are not due to medicine, maybe you should talk to your doctor about getting a sleep study and let the results of the study guide your next steps.
I'm not on any medication so I don't know
Are you on any meds that could be affecting your sleep? Not enough or poor quality sleep can cause symptoms that look like depression. Are you certain your "depression" isn't really mental and physical tiredness?
The sleep disorders we hear about a lot are sleep apnea and periodic limb movement disorder. A sleep study could help identify if something is going on while you sleep that is preventing you from sleeping and/or sleeping good.