I think weed and alcohol together can be a disaster. To the original poster, how well aware of your phobia are your friends? Do you think they might be willing to keep the alcohol consumption to a minimum for your sake? After all its YOIUR birthday, just cause most people want to get plastered on their 21st doesn't mean everyone does...maybe you want to do something a bit different...just go out and drink in moderation, or not at all...what have you. I don't think you should back out completely based on your post last night it seems you might wind up kicking yourself for not enjoying it as much as you should.