I never post on here, but as someone who has struggled with these same feelings since childhood, I thought I'd offer my perspective.
I've come to look at it like this: depression is like an Instagram filter. (Wait, just...bear with me.) Go take a picture of a tree outside with Instagram. Now lower the saturation, pump up the shadows, add vignette edges. You'll end up with something that looks like a goth album cover. Is it still an accurate picture of the tree? Yes...but you've chosen which aspects of it to focus on. You've given it an emotional coloring.
Being depressed is like having that Instagram filter on your entire worldview. You're not delusional, you're not just imagining that the world sucks...but your ability to see the full spectrum of things has been limited. And the worst part is, you can't control when that filter gets slammed down on you.
Sometimes it's situational. Here's a hypothetical for you: if somebody showed up at your door tomorrow with a check for a billion dollars and the deed to your own private island where you could go be alone or be surrounded only by people you wanted around you, do you think you would still be depressed? If not, then you know the answer: go find a billion dollars and a private island, obviously. (Go find Peter Thiel and hit him up, he's into big money and private islands these days, I hear.)
But in all seriousness, if your depression seems tied to circumstance, never forget that circumstance can change, either on its own or by your own effort of will. Unless you are actually in prison right now, you can almost always walk away from where you are and find somewhere else to be. Someone else to be, in some sense.
But you have to be honest with yourself and willing to admit that maybe you're not where you're supposed to be, even if you've spent your whole life headed in this direction. Maybe you'd be better served working as a bartender in some roadhouse down on the Gulf Coast, or living in a shit apartment doing sculpture and working part-time as a barista just to afford rent and ramen noodles. I know people who are perfectly content with the idea of never being rich or successful, but just doing what they want and not worrying about whether anybody else gives a shit at all. (I'm becoming one of them myself.)
And there's always the possibility that your depression is, at some point in the stack, hardware-based -- that you've got a chemical imbalance in your head meat. And listen, as a longtime freelancer and contractor who's been doing the startup dance for a real long goddamn time now, I feel you on the medical thing -- hell, I wrote a book about going to Juarez, Mexico to get my wisdom teeth fixed because it was cheaper to do it there, including travel expenses, than to get it done at the dentist down the street. And that shit can be tricky in America, especially if you're not actually indigent but can't afford to spend hundreds or thousands of dollars on doctors and medicine. (I think your income level at that point is legally defined as "between a rock and a hard place".)
But there are resources. If you live in an urban area there are almost certainly free mental health resources. You can go and sit in line and find out if you qualify. It sucks and it's boring and it can make you feel like a pathetic crazy person, but never forget: that's not about you, that's about the way the system is set up in this country.
Or look at it another way: if you had diabetes, or a weak heart or your legs stopped working, wouldn't you do whatever it took to figure out why it was happening to you and how to stop it, even if it meant sitting in some overcrowded janky-ass waiting room for a day?
You've got a potentially life-threatening condition that may or may not be caused by bad wiring. If there's a way to fix it, fix it.
Because here's the thing, sir or madam, and please, please take this from someone who has spent more than one night staring at a razor blade or a handful of pills: this is a fucking glorious universe we live in. Really. The moments when depression leaves me entirely are the moments when I'm just alive in the world, looking at how ridiculous and amazing it is. I don't kill myself because I'm not done with the awesome. I'm not done with eating the food and seeing the cities and sleeping with wonderful ladies and watching the Marvel Cinematic Universe unfold and listening to all the goddamn rock and roll I possibly can and just finding nice, quiet places to stare up at the Milky Way and think about whether or not this is all just one great big algorithm, playing out over billions of years.
We live in a mystery, homes, and you'll never come to the end of it. But isn't that worth something?
I hope my advice helps, or at least puts some perspective on things. I don't know you and probably never will, but I'm rooting for you. You can handle this. Don't give up. As the writer Neil Gaiman once put it -- and this is maybe the best advice any human ever gave another -- you don't have to stay anywhere forever.
Vaya con Dios.