I've been in your shoes.
You feel like garbage because you CHOOSE to feel like garbage. In a sick way, it gives you an identity, and it gives you an emotional pay-off. For me, I needed an excuse to not take responsibility for my life. I needed the attention being depressed gave me (even negative attention was ok). I was really invested in being "totally NOT ok."
Letting go of that identity is tough. It's comfortable. And, if you let that identity go, then who are you really?
I really recommend you read Eckhart Tolle "A New Earth" and watch the Oprah/Tolle webinar