Idk how do you call this emotion......betrayal?...And how do you get over t?

Yeah for me personally I can't stand flakiness, especially at that level. As rayelight mentioned above: yeah. I'd also recommend having a talk about this situation, because that's not cool. If she treats the whole situation like it's nothing or can't even apologize that's when I'd start distancing myself personally. It would definitely imply that between the two of you there is a large imbalance when it comes to how invested each of you are into this friendship.

I LOATHE people like this. I've had this problem with caring about people that don't really care about me ever since high school. I used to blame myself, thinking that there was something wrong with me, and it destroyed my confidence. Nowadays, I'm doing my best to get rid of people like this from my life. Don't expect them to change unless something extreme happens, which is rare enough to be a once-in-a-lifetime moment if even that. Surround yourself with people whose actions reflect the words that they say. If you notice someone who goes out of their way to help you, hang on to them, because they're the real ones that you need.

I don't have friends like her because I learned my lessons years ago when I was just a sensitive,friendly person.Now, I'm pretty at making myself invisible and sending intimidating vibes online and offline, so that kind of people aren't interested in me. (╯‵□′)╯︵┻━┻ A friendship should benefit both parties.

None of you know your "friends" as well as you think and none of you are saints that give everything for your friends. Now that that's cleared up... Talk to your friend, get her side and ask why she would clearly ignore you while at a public function, especially seeing as you seemed to have been uncomfortable being alone and I'd hope she would've known the before the fact. No need to just jump ship. I mean, everone on the outside is quick to say that WITHOUT looking at the big picture and then "claim" what they'd do. You've gotta be the judge here.

I'd say I have many acquaintances but few friends..but that's how i went through my life. I cut people like what you describe out of my life real fast. Bad behaviour is not tolerated. I had a best friend once who did something similar a couple of times after the second time I pretty much stopped bothering with them.

Currently,in real life I have 0 friend(as a salarywoman)!I'm happy with it! I would rather have 0 friend instead of 100 fake friends! :D Fake friends and friendships make me feel lonely.

I'm also in the have a conversation with her about this side. People sometimes make mistakes and do shitty things, unless it's something that I just 100% can't reconcile with I'd want to know what happened. I'd at least have a talk with that person to see what their side is, even if it's just for closure sake