I am sorry that you are going through this and I believe that I suffer from the same problem. I go places with people but whenever the conversation talks about something that I do not fully understand it seems that the conversation always stays there and there is nothing that I can say because I don't know anything about it. I usually get off to myself and just sit there and wait. I feel this way about family too a lot. I usually just go watch tv with the kids in the house because they are so into watching tv or talking about things that I have an understanding through life experiences. In other instances I do not want to talk about those things but I can't tell them that because they are already into talking about it. In the chat rooms here if I enter and they are already chatting about something and I don't understand I usually leave the room. I feel isolated and assume that they do not want to hear what I want to say because it is boring or not important. I have been told that I may be projecting the idea that I am not important instead of actually being non important. If this is the case then it is hard to overcome.