Up All Night

When he has a number in the 40's, its very hard to sleep that night.  I will usually stay up and check him mid-night to make sure he's ok or I will set an alarm to get up and do a check.  I especially worry when the low was out of nowhere.  No extra activity, carb counts were right, I always want an answer to an unexplained high or low, but I guess I'm not always going to get one..