Seriously though - you may have a minor fungal infection which should respond to an over-the-conter ointment from th chemist. Don't feel embarassed, it's very common, and they'll be able to reccomend a treatment. If it fails to respond, a check with your Doctor will address anything more serious that may be causing your problem.
It could be that you have worms....don't panic, they are very common and easily caught. Go to the chemist and ask them for advice. It normally only takes a small tablet to rid you of them. They aren't dangerous, just a nuisance. Make sure you wash your bedding and use a nail brush for cleaning under your nails when washing your hands.