I think your parents are right. If you are very close to the people, they will eventually want to stay in touch. People get busy, and people have a lot of things going on. It's very difficult to keep in touch with every single friend and acquaintance. Just relax, let go, and hope for the best. You can't guess what goes through people's heads. You can only control your own reactions to what they do. I know this is much easier said than done.