Summarize this article:

Take a few minutes to laugh either by yourself or with others. Whether it's a short 2-minute video of a cat wearing pants or a feature length comedy, laughing has many health benefits:  Laughter stimulates many organs. When we laugh we take in more oxygen than usual, and that stimulates the heart, lungs, and muscles. Laughing increases positive thoughts, leading to the release of stress and disease-fighting neuropeptides. Laughter itself increases mood and leads to feelings of enhanced interpersonal connection when shared with others. When you have negative or nervous feelings, it is hard to stop yourself from wallowing in them. Crack a big smile. It might be fake at first, but think about something that genuinely makes you smile, and keep working at it. A great big smile will momentarily trick your mind into thinking more positively, helping pull you out of a rut. Power posing is a way of holding your body to convey confident and dominant body language. In turn, this can help make your mood more relaxed and confident. For example, when speaking in a meeting, cross your arms across your chest and sit up straight. If you are closing a deal, show that you are engaged by standing, leaning forward, and resting your hands on a table while looking at the client or other individual.

Summary:
Start laughing. Smile when you feel nervous. Try power posing.