I went through the same thing. The best advice I can give you now is to go chiropractor that specializes in many different types of medicines. DO NOT go to a regular MD - they will not help you any.

Depression is a symptom, and can be caused by a variety of factors. You need someone who is unbiased and well educated, and a well-rounded chiropractor is a great starting point.

Nutritional Deficiencies Toxicity Malfunctioning (thyroid, adrenal)

these are all major possible contributing factors that need to be checked.

You can email me at anony304@gmail.com and I'll help you try to figure out the root. Detail in your symptoms helps too (e.g. do you get dizzy when you stand up, are you lethargic, digestive irregularities, etc).