It sounds like your T doesn't believe depression can be caused by life events and stressors, which is not true. Many people get depressed over life events, i.e. they have "situational depression"--I don't like that term myself. This causes changes in brain chemistry, and medications that act on neurotransmitters such as serotonin and dopamine, as many antidepressants do, can often be helpful in these cases.

I'm not sure why having 4 symptoms instead of 5 would make a difference in your approach. Work on the things in therapy you want to work on, such as feeling more connected to people. If you want to consider medication, go see a pdoc for an assessment. Does it really matter if you have the exact criteria for major depression or dysthymia or social anxiety disorder, or whatever? You can focus in therapy and with a pdoc on what you want to change without having diagnosis A, B, or C. FWIW, many people visiting a pdoc the first time get broader diagnoses such as Mood Disorder NOS, Depressive Disorder NOS, Anxiety Disorder NOS, etc. It's not like you have to have a diagnosis of Major Depression in order to be helped by either type of provider.

Perhaps of relevance: I take a very low dose of a medication for ADHD that is commonly used to treat Major Depression: Wellbutrin. Even though I am not depressed, this medication not only helps with my ADHD but with my overall mood and outlook. Just a little bit of extra dopamine is something my body and mind seem to do well on.

I hope you will find a new neurologist.