It sounds as though you may have had that experience early on in your life. Like, maybe a parent thought you just wanted attention when you opened up to them. If that happened, it might have given you the feeling of being invalidated, and led to a belief in you that you're not worthy of having other people listen to you, consider you, value you. After all, if someone close to you assigned to your opening up to them, something that served THEIR needs instead of yours, how important could your true feelings be to them. (I don't know if any of this is true for you. Does it feel true?)