Why does my crush stop ignoring me

Devastated because I was rejected by my crush, what can I do to get better?

Hello,

So I have to tell you my current shitty situation. (I'm male, 18)

For about 2 months I've been doing something with a friend every weekend, she stayed with me every Friday and we just cuddled and both loved it. However, I was always cautious and didn't develop any real feelings either, because I only get these when the other person shows clear signs that they like me. Exactly 6 days ago she was drunk and wrote to me how much she would like to be with me now, how much she misses me and wanted to make calls and all the trimmings. I was very happy and developed feelings over the last week because I thought it might turn out to be something (I've never had a girlfriend and have never been in love) Now she writes me that she is going to a bar tonight to meet someone see where I know who. Another one she started writing with. I'm sitting here now with tears in my eyes and I don't know what to do.

Why is she doing that?

Why does she first write to me about how important I am to her and then 6 days later her complete attitude changes?

How do I get over it now?

She was the first one I fell in love with and I really have no idea how to deal with it. I'm really in the bucket

Would be great if you could give me tips ...