Yes. Seek an expert mental health professional who takes the time to hear you & to begin to know you clinically. Listen to him/her. Engage. If that professional communicates effectively with you, work with him/her. Expertly managed psycho-active meds may be crucial, but it is a comprehensive process not just a prescription that will determine your response/recovery.
Yes. It depends on the type of depression, one of the most effective treatments for bipolar depression is n-actyl-cysteine [burke, 2008, j of psychopharmacology]. Healing breath technique was found as effective as ect/imipramine [antidepressant efficacy of sudarshan kriya yoga (sky) in melancholia: a randomized comparison with ECT and Imipramine .” n janakiramaiah et al] exercise may be a first choice.
Quacks and drugs? It's puzzling that you'd ask those you refer to as quacks, such an important question. Would you trust our response? Despite this, i'll suggest that consistent exercise has been shown to be equivalent to some antidepressants; that some people with methylation issues need l-methylfolate; that diets high in processed foods increase risk of depression; & psychotherapy can help dramatically.