Your brain is a prediction engine. It tries to predict what's happening based on how your body feels.
The problem is that your brain attributes those feelings to what's most recent.
Are you anxious about being on stage? Or was it the tacos you had last night?
Are you a failure? Or is environmental stress preventing you from performing at your best?
Is your friend making you angry? Or are you on your third day of no sleep?
These don't have to be either-or. But a lingering physical symptom will often get rolled into the recent mental problem.
Before you jump to create a story about how you're feeling, ask yourself:
- When was the last time I slept?
- When was the last time I ate?
- When was the last time I drank water?
For the want of a glass of water, the negotiation was lost.