Welcome to PsychCentral, WhatNext. You've done analysis of where you stand. What seems clear to me is that you're withdrawing for the world ... and maybe from life. Whether that's because of depression or is causing depression, I don't know.

I think the first thing you might consider is a thorough physical examination to be sure there's no underlying medical condition at the root of your situation. A slightly hypothyroid state, for example, could be to blame. Other things. I'd start part there. How long since you had a head-to-toes work-up? Unless mental illness runs in your family, odds are you're going to find your answers here.

If your primary care doctor finds nothing, and whether or not you have hereditary depression, etc among relatives, ask for a referral to a diagnosing psychiatrist. Make sure it's diagnosing doc, someone who can evaluate in a broad range.

I hope you'll check in here often. Feel free to explore the forums and post anywhere you find a connection.