There's no one size fits all solution. There's a lot of things that can help and a big advantage to having a professional who knows how to use them.
Treatment usually begins with a visit to the GP who can give you a physical and hopefully a good referral.
I've written a lot of depression answers. I'll show you one. As I said, there's no one size fits all solution. On the other hand, healthy lifestyle is something we all need.
https://answers.yahoo.com/question/index?qid=20171109014625AAKBVuX