You need to turn you head. Do'nt let you own family be a peer pressure on you. They are adults and that is there choice. I do not condon this by any means. The asnwer is no, they have no idea what it is doing to you. Have you ever really been able to talk to them about it and how you feel.
What this boils down to is that you have to think of you and try you best not to let it take you over. Take a run over to an Ala-Teen meeting once and see what it is like. I'm not sure if Narcotic's Annyomous have a teen group out yet. Just consintrate on holding yourself together.

The best you can do is talk to them. Let them know you are having problem coz of their behavior. And I'm sure sooner or later they'll understand your problem. but you need to concentrate on your life for sure.
Take care and live healthy.

The best thing you can do (coming from a parent that used around her children) is tell them how you feel! I don't know if I would have quit right away but It sure would of opend my eyes and made me think about them other than myself. We love our children and want the best for them and when we find out they are not happy especilly because of something we are doing it really hits home.