Keep posting here if you want to. This is a pretty active part of the forum, so if posting here and talking will keep your from calling your dealer, please do. I am an alcoholic but I can imagine there are similarities in our addictive behaviors. I don't know about heroin withdrawal but have a friend who has been through it and he told me that he broke the day up into small periods. I do this with alcohol too. He found mealtimes were good points of reference for him. So he would say "I will not use before lunch" and then he would have lunch and after that say "ok, now I won't use until dinner" and get to dinner, after that he would go until he went to bed.
Good luck to you and feel free to post here or on the SA board as much as you need to.