Gail, I have 4 brothers and 2 parents and only 1 of my brothers knows about my anxiety issues. They probably all know I've had a history of binge drinking, but only the 1 brother really knows that I have serious psychological issues and that I'm seeing a therapist. I didn't really want to let him in on it at first but I'm glad I did. It turns out he has similar issues and has been in therapy as well and didn't even tell me about it. We've compared notes and found that our issues have similar origins in the way we were raised. Letting my brother into this part of my life was one of the best decisions I've made.
I can see myself eventually talking about all this with the rest of my family, but for now it's just the 1 brother. I'm sure your sister cares about you and hopefully when she reads your posts and understands what's going on in your life and in your head she'll be able to support and help you in ways that none of us who don't really know you can.
Welcome aboard, Nan.