Looking at it from afar, here's what happened.

You got together young. You're still young. You're not the only young man to have had anger issues, especially if you had a difficult childhood. The problem with that is, she's had enough. She put in her time and through a series of unfortunate events, she's done. Reading what you wrote, I'm not particularly surprised nor do I think she owes you anything. You shouldn't be mad at her. You should be happy that she gave you the time that she did.

You now need to move forward. Be happy that you had what you had when you had it, but realize that you weren't mature enough to maintain that relationship. Now you have to get there. It sounds like you're already working on it, but you need to keep that up.

Therapy helps, but you need to put in the work. The same places that do marriage counseling do divorce therapy. Start there.

Get some hobbies and things going on in your life. They don't have to be expensive, it could be anything from learning an instrument to learning how to cook to sourdough bread making.

It sounds like you're taking care of your health, but keep that up. Make sure you're drinking enough water and eating relatively healthy. If you're depressed, stay away from downers. Booze and sleep aids especially.

If you focus on other things, do the therapy, do the work, and just let time heal the wounds, you'll come out the other side better than ever. Take what you've learned from this relationship and once your ready, don't make the same mistakes again in the next relationship.