I think you have to work on how to soothe yourself? When you don't feel heard, you have to talk to yourself and a journal or diary or just scribbling, etc. can help me. Or, I talk out loud, get a couple voices going discussing the issue and after awhile the whole situation will make me laugh at myself and ease my sense of injustice.

Why do you have to be heard by other people? Other people have their own things going on as you have noted and they don't appear to be very useful to you? Like hankster said, sounds like your mom is not very good at it? Instead of looking for agreement on how you feel (that so-and-so was rude by not responding/accepting your outreach) from outside yourself, give it to yourself from the inside. I suspect your friend who was "lovely" was disappointing because she wasn't there and her agreement with you doesn't mean that much? It is okay to want to be agreed with, everyone wants that, but seeking it and expecting it and being disappointed when we don't get it from others is a little like setting one's self up to fail since we can't control other people and their thoughts, feelings, and actions, only our own.