At the end of the day,there's probably little reason to pay attention to our dreams at all unless they keep us from sleeping of“we wake u in a panic,”Cartwright says Terrorism,economic uncertainties and general feelings of insecurity have increased people's anxiety.Those suffering from persistent nightmares should seek help from a therapist For the rest of us,the brain has its ways of working through bad feelings.Sleep-or rather dream-on（ it ）and you'll feel better in the morning.请问最后一句中的it指代的什么?