My bestfriend got a date to homecoming last minute?

[Erin]

She got a date with a black guy who goes to our school 2 days before homecoming she says she doesn't like him and would never date him ever. But now I'm the ONLY one in our group with out a date she's only going with him because she doesn't want to be alone and 2 months earlier he asked her to be friends with benefits on Facebook she said that he was desperate and didn't even like him and now she ditched me 2 days before homecoming after i paid for all of my stuff and I don't want to go because ill be alone and have a really bad time she did this last year too and I cried when I went home because they all had dates and left me alone. What should I do?