When we are together they huddle together and exclude me altogether
What a sad situation. We all really feel for you. Whatever the reasons, and remember we dont know all the details, you are hurting and understandably so. Its not even as if you are spaced out any longer…:-)
But seriously, if your siblings do treat you as the baby and huddle together without you then is it any wonder that your niece has picked up on this and avoids you also? She’s only copying them. They could be the problem here. You’re lucky your other nieces and nephews dont act likewise.
Let me ask a very important question. Do live near or far from this niece? Meaning does she see you often or rarely? Does she see the huddle against you often or rarely? Do her parents talk about you in her presence? Is there anyone that could act as a go between to speak to her briefly, cos if you send the letter it could make her embarrassed and much more distant, but she does need to know of your discomfort with her behaviour.
Wishing you only a happy life and may you find your Bashert soon which I’m sure will help both of you!