My three year old son for the past week every night wakens up distressed that there is a big spider on his brother bed...its as if he is awake but even after showing him there is no spider and calming him down he lies back in his bed and then it starts again by saying there is a big spider. Hes fine through the day but as soon as take him to his bed he will say mummy/daddy is there a spider, and when re assure him there isnt hes sleeping within few minutes however through the night is becoming tricky to get him back to sleep, over an hour this morning...we are exhausted. Has anyone else experienced this, how long does it last and is there anything we can do to try prevent from happening? TIA