your body needs rest you dont nesacarily need to take 2 days off in a row, but missing 2 days a week can actually help your muscles grow, because muscles can only grow while resting. muscle growth is pretty much your muscles repairing the damage you did to them and getting ready for more abuse.
and stop fretting about that cookie i had some chocolate cake today (best friends birthday) and its fine still have to do like 100 squats though.