A lot of difficult things in life are defining. The way that an early trauma can seep into the very framing of our lives, which fills the thing that comprises the self. Social issues that feel like a force of mundane evil which seek to spoil and exploit every day. Illnesses that limit what we can do in our lives create these boundaries which we might spend decades struggling against.
Struggle defines a person, it presses down, it is a force that shapes. But in a way, depression is unique. It is un-defining.
The depressed mind has been shown to form memories more poorly, retain less information, and experience difficulty making choices. In a sense, its defining trait is that other traits will fail to develop, will not be defined. Depressed people will talk about years that were "lost to depression", where they felt like time simply vanished, where life seems to have passed them without remark. Their memory still works, but the happenings didn't matter to them. Their mind would not hold onto their time, would not mark it, would look out on the events of a life, and select nothing as important.
Disappeared. Imagine whole aspects of the psychic self ignored and passed across, having the depths of experiencing life shallowed to what the disease would permit. Our selves are pulled up from our memories and our instincts and our decisions. Then, depressed, remembering things only partly, thoughts dulled, definitions badly ignored, cloaked in uncaring, the self emerges. An undefined, unremembering, undeciding thing is our being. This blurry personal history, this scatterdash scaffolding of self full of holes, blind spots, and omissions. How is this depression-marked being ever supposed to get free? How do "you" escape from a condition that is trying to unmake you, which has gnawed holes in your past?
The answer is that you have to be. Just be, harder than before. That's not a medical opinion, or useful advice, it's barely a slogan, but I feel it to be totally true. In the places where you have been marked by depression, the world passes you by without leaving a single impression on you. So find ways to remember it. Suck in freezing cold air and feel earth through the bottoms of your shoes. Find ways to surprise yourself. Take a few steps closer to danger, just for the taste of it. Recollect the past, not with calendars and appointments, but with the twitching fibers in you, the impression left by the real world on you. Take the force that's inside you, and push with it, notice it being real, and notice it being affected by external being.
It's not a cure, it's just a way to claw back the you that is in there. The one that feels and sees and knows that there is more than simply that. That living, hungry self that exists on the far side of a wall of apathy and inaction. Sunken in. It must be real, it must still exist, or else these words are going completely unheard. The one which knows it has been wronged by this disease and wants to be restored, to be made. To having been deprived form, deprived definition, deliberately create a necessary self. Been so long this null thing, defined by reactions and void, the happenstance of the world, so instead manifest that sole internal being. Let yourself make you.
For a long time, I used to believe that most advice is bad advice, because it's usually said by someone who is fully or partly recovered, less helpful for someone who feels buried beneath the crust of this big awful thing. If you are deeply submerged in this thing, then it's possible that no words are useful at all to you. Still, I think it's important that you read this. My progress is going well, otherwise I wouldn't say something like this. I know that this is a solitary journey, a slow and chronic crisis, and I know that as closely as I feel that my words are true, they might utterly miss you. My words contain truth in a personal sense, and to the best that I can think/believe, to be true for others. I hope this is valuable to you. At least, I hope it is interesting.