The first secret to depression and anxiety is to compartmentalize and accomplish the small things one at a time in order to diminish the pile. It's easy to "scope creep" your way to despair - note that you list four things as if they're cumulative, rather than symptoms of the underlying problem.
Do the thing you can do now and do it now. Do not frame it in reference to the millions upon millions of other things holding you back - strike against this one thing, now, and get it done. Then once that's done, strike against the next thing. Then that night, write down on a piece of paper what you accomplished - and below it, what you'd like to accomplish tomorrow. Be realistic. Be conservative. And be forgiving if you only hit half of it.
The other secret is exercise. I reckon it isn't exactly walkin' weather in Novosibersk at the moment but if you can find a swimming pool, buy some goggles and do some laps. It's contemplative, it's isolating, and it will put you in a place where you can let the monsters run through your head in a place where the only thing on your plate is facing them.
This is not a battle you will ever win. Eventually you will fight the enemy back to the demilitarized zone where you can keep them safely at bay and lead a normal, happy life... but the sooner you get into the mentality that you must fight for your happiness, the sooner you will start protecting your perimeter against incursion.