Textbook depression. Since you're posting in the NEET subreddit, I'd hazard a guess that it's primarily due to life circumstances. In other words, if your life were to improve, your depression would improve.
Try getting a job. That's what saved me. I was horribly depressed before getting a job, now I'd say I'm doing okay. Not perfect, but I'm really doing okay. Here's a list of the things that getting a job did for me.
Greatly reduced my social anxiety. Interacting with a combined hundreds of acquaintances, friends, and strangers on a daily basis has been amazing for my SA. I now enjoy meeting new people. I'm no longer fearful of talking to attractive women. I'm not so neurotic about little daily interactions.
Improved self-esteem. I view myself in a higher regard than I used to. I'm no big shot, but I have a role in society. I have money to spend. I have a skill set that others don't. I deal with adversity on a daily basis. That's been huge for me.
I enjoy my free time so much more. The feeling of getting home from a long stressful shift and just laying down to watch a movie or play a casual video game is so amazing. Having a day off feels so great. Going out to a restaurant or bar with some friends is even more fun than it used to be.
Money. Self-explanatory.
I've expanded my social circle and met some awesome people. More social opportunities is always great. If you don't have much of a social network already this is a life-changing benefit.
I could go on and on. But life is really so much better now than it used to be. Seriously, take the plunge and see what happens.