We are not professional medical staff here so the answer you'll get is base don experience and knowledge which you might find limited.
There is many forms of depression. I have depression on one side of my bipolar for example, others clinical depression and so forth.
Each sufferer has their own story of origin and reaction to depression.
Apart from the obvious with GP visits, medication and psychologist/psychiatrist visits there is group therapies and forums like this. Brain storming people like us, fellow sufferers can give you real life ideas based on experience like-
- changing your environment say from the bustling city to the country where its calmer
- Removal of toxic people from your life
- More ideal career path like working alone in some professions
- Better sleep and consider a sleep study
- Good diet and regular exercise
- A family pet
- Hobbies and sports
I hope that helps. Use search to find other threads on this topic. eg
Depression and sensitivity a connection?