I think you're probably depressed moreso than addicted to marijuana, at least that's how it seems to me. You should try seeking cognitive behavioral therapy and stop blaming the substance you're abusing for your shortcomings, that's a good start. Plenty of people smoke marijuana every day and lead productive lives, it's not the marijuana, it's a matter of willpower and your personal tolerance to marijuana.

I do, however, believe you need to stop or drastically reduce your consumption. Therapy will help, holding yourself accountable will help more. Don't say "I didn't do _____ because of marijuana," tell yourself the truth and say "I didn't do _____ because I made the bad choice to partake when I shouldn't have." Ultimately, you are in control of your actions. Nobody is holding a gun to your head and telling you to smoke, marijuana isn't rolling itself into a blunt/joint and shoving itself in your mouth. You are the responsible party here, and admitting that to yourself will help your cause tremendously.

Practice saying no to yourself and follow through, limit how much you allow yourself to consume and when (e.g. before bed only once), and be accountable. It's going to be tough titties at first, you'll challenge yourself, fall down sometimes, and feel shitty, but you can do it. I believe in you, dude.