Trombone-I realize that I neglected to say in my op that the sister having a bbq was a relationship I treasure. There is a long story behind it but it matters very much to me to have her and her family in my life. Unfortunately my mother lives with her. So, the situation is complicated.
However, I feel that even had I not added that info it doesnt change the fact I was looking for advice on how to work on my tendency to over think things. To play different scenarios over and over in my head until I am a stressed out mess.
I was not looking for comments about how others just dont get involved with their families