Depending on how bad your hangover is, you may just need to sleep it off. If you can sleep in, great! If not, try to take a nice long nap later in the morning or in the afternoon.
Alcohol messes with the pituitary gland when you drink, which throws off hormones and confuses the sleep cycle, making it impossible for you to enter the REM stage of sleep. Try some Sleepytime Extra Tea fortified with Valerian root to help you catch some quality zzz's.