Here is an article from WebMD that you might find interesting. You might also go there and asked the question about the weight gain. Just a thought.

Sleep and Hunger Control - There is a widely studied hormone, called leptin that signals the brain when we are full. When the body doesn't get enough sleep, hormones in the nervous system are triggered that can lower the level of leptin. When leptin levels are low, the brain tells the body it wants more food. When you get enough sleep, leptin levels stay high and let the body know it is satisfied, thus decreasing the need to overeat.

How Much Sleep is Enough? 7 to 9 hours a night is the average amount of sleep recommended for an adult. Experts say you will know if you haven't had enough sleep if you feel drowsy during the day. The human body does not seem to adapt to sleeping less, creating a 'sleep debt' that the body will eventually demand be paid back.

How to Get Better Sleep - First, move your TV and radio out of the bedroom. Keep your sleeping area as dark as possible, as well as cool and quiet. Make a relaxing pre-bed routine, such as having a warm bath and a cup of decaf tea. Don't do stressful activities before bed. Try to go to bed at the same time every night and wake up at the same time every morning. During the day, be sure to fit in some activity. Make your 'to-do' list for the next day to keep from focusing on upcoming plans at night that can make well-deserved sleep harder to get.