What to do if your best friend ditches you??

So i had a best friend but today i got a text from her saying she wants to hangout with one of her other friends and i did not understand her message i said sorry i dont understand and she said she doesn't get the part i dont understand and was being very rude to me i know i have other friends but at the end of the day we were really good best friends and had everything in common and trusted her so much and i am so dissapointed and shocked in her actions i have no words speechless and the only thing is when i went to her house for a sleepover her parents have very good money and bought all of them large drinks and bought me a small drink that made me feel very sad when you go to someones house you treat them fairly and respectfully and also i couldnt imagine words come out of her mouth like that she was so shy nice and caring but i know i need to stay positive and also the problem was she never texted me and never called to say hi how are you any ideas what to do at school tomorrow she was my only friend i really had she knew that and then dumped me i honestly dont know anymore! :( any suggestions???