I don't know you at all Angry Hippo, but to be honest you sound a hell of a lot like me about five years ago. All I can say to you is that if what I think is true, you don't need your parents or anyone else for that matter to confirm who you are and what you want out of life. I suffered through bouts of depression for years, and still do to some extent, but it does get better. Someone advised you to do some volunteer work; this sounds like a good idea if you like that kind of thing, but if not I do advise you to do something that you are going to be proud of, whatever that may be. Become your own person, seperate from your parents and you will be a much happier person, and if you are anything like me, your relationships with your parents and others will improve as well. Wish you luck.
PS. If you are depressed, weed is probably not the best way to handle it. I self-medicated for a long time, b/c that was the only way I could feel good, but in the long run it's not a very good idea. just my two cents...