Anon, if you really were a bad person we wouldn't be having this conversation. If you were a bad person you wouldn't care about any of this enough to be as depressed as you are. You would do your drugs, get your free government money, and just laugh about it all. If you were a bad person your only reason for keeping yourself alive wouldn't be 'because people need me.'
You are a good person in a bad situation. I truly hope you can learn to enjoy your drugs and lifestyle without feeling the need to perpetually attack yourself for it. We are all victims of circumstance. Please don't make it harder on yourself. Maybe, one day, you'll manage to quit and get your life together. Not today though. Probably not even in the near future. You just need to focus on accepting yourself, and enjoying the moment. I know it's hard but please try to understand, in the same regard that you never asked for this, people who are out there being happy and living good lives didn't ask for it either. It's all just luck of the draw, in the end. You can't change your hand, but you can make the best of it. It'll just take slow, deliberate steps.