I have pinworms, they are not going away. How long doe the med. take to work?

I have had pinworms for two weeks and I'm getting very tired of cleaning my sheets and mopping my floors. i have taken two doses of mebendazole and they do not seem to be going away. How long do pinworms live after the medication is taken? My family has been treated but does not seem to be infected. Please help, they itch very much and are uncomfortable to say the least. Thanks.

Vanessa Smith