What is depression? How does it feel like?
I have successfully vanquished depressive illness (acute or clinical depression) - although depressed states do recur now and again (chronic depression) - and have some thoughts to share on the topic.
Depression, rather like the AIDS syndrome for physical health, occurs and takes hold when the mental immune system has been disturbed, perhaps because of some particularly stressful episode or event (bereavement, humiliation, social isolation, romantic break up or some other trauma), unhelpful habits of thought (perfectionism and elitism being two of them), and often comes with other states such as anxiety, low self-esteem...
An average day has its share of social interaction, things to do, commitments... When one is depressed, that is, when one's mental immune system is low, little hiccups (a bad interaction with a bus driver, a car honking) tend to knock one out and set off a train of negative thinking which in turn causes stress and a depressed state through the agency of the so-called cortisol hormone.
As many philosophers have pointed out, reality is linked to perception. Or, in the words of Qui-Gon Jinn to Anakin Skywalker in Star Wars Episode One,
"Your focus determines your reality."When one is depressed, that is, vulnerable, the darker and more melancholy aspects of existence come to the fore, the body is flooded with stress chemicals which prevent enjoyment and activity and makes all of life much harder and interaction more threatening because of the greater possibility of being hurt and wounded.
And one need not look hard for them, even in one's own home: the News, the Rat Race, idiotic internet posturing and social media, mediocrity, stupidity, Politics, the Economy, difficult and unpleasant people, the pressure to succeed and be happy, Governments, Celebrity rubbish and so one and so forth...
Depression lowers one's mental immune system so that the negative and sad takes precedence, the more questionable aspects of existence come to the fore, what causes pain and hurt is more present in one's mind, to the point often that committing suicide can seem preferable to living and even desirable.
Once the depression lifts and one's mental and emotional immune system is up and running, then it is possible to partake in one's usual activities and occupations and not be overwhelmed by reality, mediated or not, and the triggers which can lead to a depressed state or, as in a Hinduism, a wounded chakra such as the heart and head areas.
The best recipe I can suggest for a depressed state or a wounded chakra is to first realise that all is not well in one's body and psychology, to then deliberately summon - as hard as it may be - happy, comforting and soothing memories, thoughts and images - the so-called Patronus charm in Harry Potter, to at the same time banish all stressors including stressful thoughts and rumination and activities (including internet-ing) and to sit the depressed state out with a minimum disruption to one's ordinary functioning, in the certainty that the depression and vulnerable state will lift in time following these steps. Sleep also helps in my experience.
Addendum - A recipe I use with some success for chronic depression is what I call positive-bingeing. Positive-bingeing is literally sustaining happy thoughts, memories, angles in one's mind during one's waking life, so that, for example, even the most painful or unpleasant memories are reinterpreted in a happy light, repeating mantras in one's head such as "everything is beautiful", "I love life", summoning the most confidence, security securing, resilient images, words, memories regardless of external context - in a word, mindfulness. It can really make the difference between a mediocre day and a bad day and can even make a mediocre day a good one when genuine causes for joy do eventually and necessarily occur.