I understand that it is probably annoying if people talk about your health issues and that it feels awkward when they tell you details about other people's life. anyway I wouldn't be worried too much. if they talk like that it may simply mean that they care. for example I don't think anyone is gossiping about me because I don't feel like I am important enough to anyone. so I would feel even a bit appreciated if they did. I would say it it very important though to think about what persons you want to share what information with if you don't want it to be spread.