First of all Artchic, how you are feeling in this statement is actually how a lot of people can struggle with feeling. What is good about your thread is that in your thread you have included some "whys" to how the challenge developed in you. As a child growing up you did not get the attention you needed from your parents and a lot of that had to do with the challenge they had to face with your brother.

There are times when I have come across a younger member ranting and angry, and I have to say their rant is often because they did not get what they needed from their parent due to a challenge, in one case a tragic death, of a sibling.

Unfortunately, that can lead to a void in a child that presents them with struggling as they grow and try to interact with their peirs. Often when they come across the average peir challenges where friends can engage and then ignore, they get "emotional" because of how it reminds them of how they did not get the attention they needed from their parents either that actually "hurt" them.

It could be that you can get too aggressive with others, and depending on how the other individuals are themselves, they can get rattled by that and often that ends up in distancing. It's important to understand that if you demand control too much, and you don't "share" and "give" in any relationship, you will end up being alone more.

In observing my daughter with her different friends, the friends she always distanced from were the ones who were too possessive and pushy. These were typically the peirs that I learned had so little parental parenting and their effort to have a relationship with my daughter was often overbearing and too demanding. Also, it was the boyfriends that presented this to her that became problematic for her as well.

What you have described struggling with is "abandonment issues" and the first part of making self improvement on that is recognizing it and having an interest in getting help for it.