You are out cold and unable to respond to what is going on around you.
When you gain the Unconscious condition, you fall Prone and drop anything you are holding. You cannot take any actions unless an ability specifically says you can use it while Unconscious or unable to act.
While you are Unconscious, you treat your INT, CHA, WIS, STR, and DEX Attribute Modifiers as being -1 instead of their normal value for any saving throws or skill checks you make.