I can totally relate FS. When I would "quit" and find myself visiting the dope man after a few days or weeks, it was euphoric when I was sitting with him toking up. Then I'd go out to my car and sit there with a bag in my lap and think WTF did I just do. I'd even cry about it somtimes, but I'd never throw it away. I can't tell you how many times I went through this. It's gotta be even harder for an alcoholic. At least I had to go out and activelly seek my pot. You can get alcohol just about everywhere, it is so easy to give in.
You might really want to consider giving some kind of formal program a try. AA, outpatient treatment, addiction therapy, or a combination. Just trying to "white knuckle" it doesn't seem to be cutting it for you, and you are certainly not alone there. For me, it was only when I started addressing the issues surrounding my use that I started making any progress at all. It still won't come easy, but if you at least have a "team" of some sort working with you, it can really help. Take care.