Shyness is the awkwardness or apprehension some people feel when approaching or being approached by other people. Unlike introverts, who feel energized by time alone, shy people often desperately want to connect with others, but don't know how or can't tolerate the anxiety that comes with human interaction.
If a crowded cocktail party feels like a holding cell to you, even as you gamely keep up your end of the chatter, chances are you're an introvert. Introverts are drained by social encounters and energized by solitary, often creative pursuits.
Anxiety is a normal reaction to stressful situations. But in some cases, it becomes excessive and can cause sufferers to dread everyday situations.
This type of steady, all-over anxiety is called Generalized Anxiety Disorder.