When you're feeling sorry for yourself, do something about it, says Pauline Wallin, PhD, a clinical psychologist and spokeswoman for the American Psychological Association.
For example, if you don't have an invitation to a holiday dinner, make alternate plans.
"Consider volunteering at a Feed the Hungry dinner," Wallin says. "Focus on someone other than yourself. If you're elderly and isolated, call some people. Just a call to say 'How are you?' is very much appreciated at the other end."
To keep yourself from feeling deprived during the holidays, don't banish all your favorite foods.
If you're feeling self-conscious about your weight -- for example, about how family members will react when they see you -- give yourself a reality check. "They're not going to reject you," says Wallin. "Do you reject people based on how much they weigh?"
"After all, Aunt Hilda's brownies come around only once a year," says Wallin. "But if you tend to pig out on cookies, don't go to cookie parties. Have a couple at home, and stop there."
It's also important to get plenty of rest. One recent study showed that sleep deficiency is very stressful on the body.
"Stress wears you down during the day. When you're tired, you lose your willpower and you get into arguments easily," Wallin tells WebMD. You're also more prone to overeat, or to feel the holiday blues.
And by preparing yourself for the situation, you can keep such negative thoughts in check.
Her advice: "If you feel self-conscious, you're better to deflect it right away. If you bring it up, it won't be an issue any more. Tell them, 'Other than this weight I've gained, I'm doing great.' Then change the subject."
Avoiding social events can just sink you farther into the holiday blues. So if you're shy at parties, go prepared with some small talk.
"It's the concept of 'the elevator speech': a 60-second spiel about yourself, maybe about your job or your recent trip to England, or whatever," says Wallin. "Or ask other people about themselves. Comment on what they're wearing, on the flashy earrings, on what you're eating. Talk about anything. Parties aren't about what you say, they're about relating to others."