My two cents,
There's being in a sad mood, having an off couple of days, being in a funk...
and then there's depression.
Depression is all of the above, multiplied by a magnitude of 3 over a period of two weeks or more. Depression feels like you've been dragged through the dirt and left stranded. It feels like you're alone and you don't know what to do with anything. You feel sad, but more often than not, you feel tired in a very emotional and spiritual way. Sort of like being tired of existing, but you don't want to kill yourself necessarily. You're just tired of everyday being so hard to get through with enough energy to take care of things that need to be done and care about the people in your life. When depression is pretty severe, you might not even have the energy to eat, do something that might bring you some momentary joy, or even get out of bed. Your thoughts are slow and ponderous, often going over what you think is wrong repeatedly throughout your waking hours. Because of this, you may get sucked into a negative spiral of thought where your mood dives lower and lower the more you think about the situation, and it's very difficult to stop thinking about what you feel is wrong or think about the problem from a different perspective.
Yeah, the idea of 'tiredness' resonates.
A post I made a fair few months back because I'm lazy (and should be doing school work >_>):
"The worst I've felt is either the feeling of fading way into nothing, an unbareable nothing, the better moments of it being an ocassional buzz of low to non exstent 'contentedness', a kind of apathy. One big shade of grey fading to nothing.
Then there's the kind which is more anxiety related, panic - so natural to you it's become dull, normal - festers in the pit of your stomach almost constantly, untill you forget it for a few moments. Something seeps into every inch of you, making you lethargic and leadened, but also nausiated with anxiety. Something resting in and on your shoulders, a dark kind of...it drags you down, lifting your head is an effort, makes the muscles in your face feel like they're hanging from the bone limp, and yet at the same time...'nauseated with anxiety'. It's impossible to smile, but some how you manage it, and eating makes you want to throw up. You can't get away from it because it's with you every moment of every day; unavoidable, unbearable.
It becomes normal and turns into this strange 'tiredness', drains the energy away because you're starting to squash the reality into a box you don't have to think about because it's already exhausting enough..."
Plus "Funny...I can relate to the vision part...not things changing or becoming distorted, but...everything was, visually, far duller, flatter in the periods it took over..."colorless, dull, dark", far more 2D...in a sense..."
Essentially it vibes sort've like Over by portishead for me. Out side you're on auto pilot, you can function while it's in the numb stages (so *insert word I can't fathom at present* you neither feel or care that there's nothing switched on inside), but...distant...
There's this...static inside your head, which is getting louder and louder, so loud you'd do anything to stop it, you're getting deafened by silence, and yet this other small part of you is terrified of what might happen; what might be left over; what you might do when it does. The tension builds and builds and it's just a question of when, why and how it all comes to a climax (negative orgasm much, lul).
In short; heavy, tried, dark/muted and 2D.
EDIT: Something that I think makes it easy to identify is when you come out of it (I'm talking having moved on mostly (aka not a quick process), and you start to uderstand what it is just to be...bareable in you own skin - you're not good, it's hard to believe things will ever be good again, but doing thing...as little as being able to just lie in bed reading, making your self dinner, and sitting in watching the tv, is...I don't really know how to put this)...
There's almost nothing quite like it, the one thing I can relate is when you're on your period, and you're experiencing pain so bad you genuinely want to die, anything to make it stop (I'm not even kidding), and then it stops, and you're okay, and you're light and
gentle as a feather, and just lying there, sweaty and disgusting, is more beautiful that anything you could ever have concieved of before.
I guess it's like the first minute or so to Charlotte Churche's confesional song...
It's like you're actually in a place where it's okay to get better, not exactly help, but...
