Depression is always hard to understand from the outside, even in hindsight. Hard to explain, I guess it has to do with it being a flawed mindset that defies logic. Therapy helps some people but didn't help me, as I overanalyze everything and thinking too much only enables passive wallowing tendencies.

I was a depressed, underachieving waste of space, mooching off parents and hating myself for it but feeling too incapable of making it on my own. It didn't help that I come from a family of hoarding fundies and grew up to find their worldview and dysfunctional lifestyle utterly repulsive. They put up with me because of chronic medical problems that could be fatal if untreated, and I was under 26 at the time. The thing about a dysfunctional living space is it feeds and is fed by depression. I hit bottom psychologically when somebody I wanted hurt my pride, vanished like a vapor trail, came back a year later with a lame apology and then gave me a dumb speech about my failure to produce butterflies in his tummy. This ended a streak of me being in control of my relationships that had gone unbroken since college. I realized life is what I make it, and took charge of a few small things in my life. I joined a gym and got fit for awhile (it didn't last but it helped get me out of my rut). I got a part time job, worked hard at it, got recognized for some achievement and earned a promotion to full time status after a few months. Bought a car, moved out, realized I hated my job and pursued every opportunity for advancement to other departments. Met the love of my life, who inspires me and who feels incredibly lucky to have found such a perfect match. Got promoted to job I like. Moved in with lover. Got engaged.

TLDR; Idk, but try exercise and setting personal goals for your own sake. Don't worry about disappointing anyone but yourself (and if you disappoint yourself, try again or try something different).