My best friend suddenly stopped caring me about me just over an month no

No explaination , nothing. I thought having over an month off work would improve our friendship and bring us closer but it did the complete opposite. She promised me before I taken the time off we would still be best friends and nothing would change but she lied to me. I feel so alone , I feel like I have no friends at work now because if we arent friends I will loose all the rest as they only became my friends since I was friends with her