Progress is often slow and painful and it's easy to lose perspective on where you were, where you are, and where you want to be. Reflecting on your goals and your accomplishments can help you maintain perspective and stay positive. Also reflect on your mistakes so that you do not repeat them. Don't beat yourself up over mistakes, everyone makes them every day, you are just more aware of your own. If you are kind to your future self it makes it easier to have a positive image of your past self which can improve your outlook on the future. To me that is what meditation is all about.
Since you smoke, maybe try and use that as a reward. Right now it sounds like a coping mechanism, which can help, but it's no replacement for feeling and dealing with your emotions. That's dangerous long term. In the morning, before you wake and bake, read a chapter in a book. Do 10 push ups and then get high. That way you start the day on a positive note and knock out one or two of your daily goals right away.
If you are isolating yourself and not going outside you might also have a vitamin D deficiency from lack of sunlight exposure. A daily multivitamin can help with that and other dietary deficiencies. You aren't alone in what you're feeling and it can get better as long as you try. Good luck!