Trying to make a long story short...

My son’s birthday is July 15th. He’s autistic so he doesn’t keep in touch with his friends from school. My husband’s cousin has 3 smaller children and one of our friends has 3 smaller children that my son gets along and plays well with. I originally planned to do my son’s party the weekend after his birthday. Our friend said he would be out of town that weekend. I asked him if the 14th would be good because I wanted children for my son to play with at his party. Our friend said that the 14th works. I made sure with everyone else and everyone said they are available. So I sent invitations. Now my husband’s cousin made plans and so did our friend so they won’t be attending the party. So it’s just going to be my brother, sister in law, my 9 month old niece and my mom attending the party. I’m just upset (not mad) because I planned his party trying to work around everyone and made sure the date works so my son can have children at his party but now, they make last minute plans to do something else. Am I upset over nothing? Would any of you be upset? I just want to cry for my son because now there won’t be any children there for him to play with.