a bit crushed and upset

My family has always been really close. We it seems the older we get the further I am being pushed away. My sister and I have always had to work at getting along, but my brother and I have always been great. My brother and his wife moved 1 min from my sister about 9 months ago and ever since I have been getting the cold shoulder. My brother even playing threatened me with a knife in public in front of my son...... we were at a birthday party and well it was 8 and 30 min past aarons bed time so we had to go...... aaron wanted a ballon so i went to get him one.... well my brothers kids were not done eating because they got there an hour late...... He actually pulled his knife out and opened it at me and growled. I know its silly that i am upset about this but its been the way he and my sister has been treating me lately..... and its getting really old. Like my feelings dont matter...... I am really considering not going to his bday party next week.