What Causes Itching In Lower Extremities, Pelvic Pain And White Worms?

I think I may have pinworms? My lower extremities itch constantly. I've just recently experienced a sleepless night after lower pelvic aching. I constantly have cramps and I found a little white worm the size of a staple in my underwear. Will this go away on its own? Is it dangerous if not treated? I'm kind of frightened. I'm not sure how to tell my parents also.