I'm sorry you are feeling so bad right now. You are not alone. There are many people here who can relate to how you feel. Unfortunately depression is not something you can just turn on and off when you want to. The only way you can support your sister is to be there for her when she decides she has had enough. Until then she will only resent you for interfering and not liking her boyfriend. Just let her know you are there for her. There are many forums here beside the Depression forum. You might try the relationships forum for your sister or some of the social forums might be a good fit for you. There is a loneliness forum there you might want to try.