Mean People do Suck

So today. . .somehow even when we confined to our house because of nasty weather. . .my feeling have been hurt.
It was partly my fault because I was facebooking. . .just too much. Well so I go to check the home page. . .and there is a fellow mom whose son is friends with my son. My son is in first grade but when he was in kindergarten he ran around with a pack of boys there were four of them. They always played together etc. We try to get the boys together every so often. . .maybe I don't participate with that enough who knows. But today she decided to invite the two boys not my son over for a sleep over right on facebook where everyone can see. . .now she knows I am going to see that. . .we are all friends with each other on facebook. The thing is her actions really don't bother me. . .and of course I didn't tell my son because that is just cruel. . .and honestly he has his brother and I don't think he would really care. What bothers me are two things. The feelings that this has brought up for me. . .that childhood feeling of being left out. I hate that. Plus it is ten times worse because it is your baby. . .and if you are a parent you know it is one thing to mess with mama but to mess with mama's baby now you have done it! It just got me thinking I can't let this upset me. . .what am I going to do when it goes to activities like sports, or music, or whatever he is interested in and he doesn't make the cut?
I don't want to be like what I was exposed with as a child. . .that was not fun. Not only was I rejected but then my mother would question me as to why I was rejected. I wouldn't hear the end of it for days, week, months. I am not kidding. Parenting is hard. Man o Man.