I have a group of school friends who I would consider good friends. On Facebook another friend posted pictures of a weekend away that I knew nothing about. 2 others also weren’t invited - one lives far away and one hasn’t been very well. I’m due to go to lunch in a few hours with them all - this has been arranged for months- I have made the booking. When I texted one of them to say I had seen the photos there was no apology just “my bad”. I work in a school so sometimes it’s difficult to get time off. What would you do?