I'm upset about being uninvited to a party.
Why do you care about that party?
I was invited to that party as a guest, I'm just as important as others as a person.
That must feel horrible to be uninvited, but there's no point in mulling over it anymore. They had their reasons to not want you there anymore, and you have to respect that whether you like it or not. You don't have to associate yourself with them anymore if they are being mean to you like this.
Fuck them. I'll be awesome.
Yeah, you don't need to be invited to everything.