Were you nervous about something? When we get an adrenaline rush due to excitement, nervousness or anxiety, all the blood rushes to our organs and away from our limbs making our skin feel cold and clammy. Normally you end up taking small quick breaths and very deep ones which makes you hyperventilate. Hyperventilation will cause numbness. I made myself hyperventilate once at the age of 10 to the point where I couldn't walk anymore because my legs were so numb. I have had GAD my entire life due to a minor heart valve defect I was born with (MVP), so I know all too well about what stress can cause.
If this occurs frequently, you may want to see a doctor to rule out hypoglycemia, diabetes, heart problems, or poor circulation.