I think posting on FB is going to prompt many people to ask you all sorts of questions. If you can't trust her and you don't want her to tell others then I wouldn't tell her. Maybe just say Jan detox. But I think the fact you posted on FB will make people think there is more to it than that. I don't like FB!!! Plus you can't control what other people may say to your post-someone who knows you have an alcohol problem may post something in all innocence, assuming everyone knows.