I have been depressed several times in my life. 3.5 years ago, almost suicidally. I was making plans of suicide, but not attempts.
Obviously, I'm still alive and I feel much better now. Not that I don't have problems now. But one simple change helped me feel much better:
Feeling good is a choice. You don't need anything else in the outside world to change, any circumstances to change, to feel good and be happy. You can be happy, and then change, or work towards accomplishing your goals, or making progress. You can feel happy by simply choosing to be happy.
Then I developed what I call, "Happy morning routine". It consists of 2 minutes of "laughing exercise". And then 12 minutes of gratefulness meditation.
What's laughing exercise? Simlple. Just laugh for 2 minutes. Several good belly laughs.
Use this video if it helps: (I can't watch this and not lough)
Or this baby laughing:
Try it. Every morning (or whenever you want) just start laughing. Laugh for 2 minutes for no reason at all. Or remember a funny memory or a joke. Or watch something funny.
Then tell me how you feel. It is quite hard to feel bad after only 2 minutes of laughing! :D