From personal experience (I used to lie on the couch wishing I'd die every day for weeks) I can recommend the following three things:
* Move your body in sunlight. I'm not talking about becoming ripped or doing and Ironman or something crazy, I am simply talking about doing an amount and intensity of exercise you can sustain a couple of times a week every week outside when the sun is out. Once I did this for three weeks or so I found that this dreadful feeling of emptiness faded and that I hardly felt discontent anymore. These feelings return when I stop doing that which usually is my trigger to start again.
* Read & follow the book "The Happiness Trap" <https://www.amazon.com/Happiness-Trap-Struggling-Start-Livin...>
I'd credit this book with the single biggest impact on my life. I remember crying from relief after doing one of the exercises.
* When you got yourself together somewhat I'd recommend having a child. It's the most fun and satisfaction I ever had in my whole life and it makes everything else so much better.
I hope this is useful to you and that you get better soon.
Here's a good book on the subject: https://www.amazon.com/Happiness-Trap-Struggling-Start-Living
I recently read The Happiness Trap by Russ Harris. You may benefit from it.
The book 'The Happiness Trap' helped me. It was recommended by a psychologist. There is a illustrated version, too. https://www.amazon.com/Happiness-Trap-Struggling-Start-Living/dp/1590305841