How can I help lift myself out of a bad mood?

Many ways. There are many ways to improve mood. One excellent way is to do vigorous exercise as this raises that good hormone, adrenaline, which in turn raises endorphins, the "feel good" hormone. Lots of other ways to help as well.
Bad Mood. Exercise aerobically every day, sleep at least 7 hours a day, maintain good nutrition and confide in close friends for help uncovering what is causing your low mood. Best wishes.