Hey, I don't know you at all but speaking from experience this is how I see it.
Get off the weed, or at least use it more rationally, if you want to make changes in your life then the last thing you should be doing is smoking cannabis all the time, seems like you're quite paranoid about a lot of things (getting pissed a lot doesnt help either). Clear your head, look at what you want and start making aims a step at a time, achieve those aims and then move onto bigger and better ones.
I had a friend like you, he did nothing with himself from the ages of 16-19 cos all he wanted to do was smoke weed all day in the week and get mashed on weekends, now he is 24 and in the RAF doing very well for himself, hasnt touched weed since, drinks socially and is such a better person for it.
I don't mean to sound a dick, but life is what you make it. I'm aware this is a rant but realising your issues is the first step towards making changes, I hope you can for the sake of you!