Of all the wellness changes you could make to be healthier this year, unless you need to quit smoking, sleep needs to be your first priority. Sleep deprivation (sleeping under 6 hours a night) causes obesity, diabetes and premature death, not to mention poor work performance and irritability. Your risk of diabetes is increased up to triple by sleep deprivation in some studies, and diabetes measurements (like Hbg A1C) improve significantly just from sleeping enough. Check out this summary of studies.
Most adults need 7-9 hours of sleep every night, and women need an average of 20 minutes more than men. If you are still sleepy during the day after enough time asleep, you could have a medical condition such as Sleep Apnea, in which people partially wake up many times a night due to obstruction of breathing, without necessarily knowing this is occurring. This is particularly common in people with obesity, and can make it harder to lose weight. Many people also have trouble falling asleep or staying asleep. Healthy sleep habits can help a lot to decrease this problem. Discuss the problem with your doctor and check out this link.