Tossing and turning? Watching the hours crawl by? Even one night of poor sleep can make you an exhausted, irritable, sugar-craving beast the next day. We all have the odd sleepless night, but if sleep loss goes on long enough more serious problems like hormone imbalance, immune dysfunction and weight gain can result.  Let’s look at the latest research to see what’s going on when you’re asleep, the relationship between sleep loss and other health conditions, and how you can…