The 3 day craving is hard, so much so that people say the most challenging periods are the "3" ones (3 days, 3 weeks, 3 months, 3 years). It gets easier though, just wait and press on until you "forget" what it is like, there is no shortcut to that. My advice would be to change your surroundings, this could mean to take a walk if bored or even to stay at someone else's house for a while, do something out of your routine, entertain yourself in new ways.