If you're not psychotic, but plainly depressed, the question is basically if you need your serotonine or your dopamine/noradrenaline boosted. A blood test can tell you that.
Other than that:
. Go outside every single morning. A study in a german hospital showed that 20 minutes of daily exposure to daylight can reduce meds by 30%.
. Go running for 15 minutes every single day. I say 15 minutes because it's supposed to become an easy "no-brainer" ritual.
. Keep a diary in which, every single day, you make a list about strictly only the positive things that happened that day.
I just wanted to add. If these things don't work, or you are feeling suicidal, or haven't talked to anyone -- please talk to your doctor. The same treatments will not work for everyone and it is not your fault if a regimen doesn't help or you can't stick with it. Even 15 minute no brainers are difficult when you are depressed.
Also, be honest about your symptoms. Anxiety may be easier to talk to your doctor about, but you can wind up prescribed addictive narcotics that will hurt rather than help.
You have to keep in mind that the vast majority of psych-related clinicians are average to below-average performers that were too incompetent to become real doctors. That would explain why your "doctor" doesn't understand anything taught in a basic undergrad neuroscience survey course.
It's like expecting an auto mechanic to design a new car engine - sure, they could try their best, but at the end of the day, they're still an auto mechanic, not an engineer.
And that researcher is not accessible to the general public. The strange thing is that we now see people on the internet fora doing the metabolic/neurochemistry research themselves, for lack of better options.
Yes see a doctor. However, I feel that doctors often take a sledgehammer approach to mental illness, prescribing SSRIs and/or MAOIs whenever they hear the word "depression" or "anxiety". I'm not a MD, but after reading a little about the topic, it seems that a much better approach is to see what could be the cause of the deficiency in certain neurotransmitters. The reason could be that some of the enzymes involved in the process of producing them are defective due to genetic mutations. Certain tests (such as provided by 23andme) could reveal these defects, and could in theory provide much better treatment options. In many cases this could even start with taking certain dietary supplements, which help the body create the neurotransmitters. Such an approach seems so much more sensible than just "drowning" the brain in neurotransmitters, which is basically what SSRIs and MAOIs do.
However, I have yet to see a doctor that knows anything about metabolic pathways and such.