anxiety and what comes with living the life I have

Mistake?

So I have some very close friends whom I am very happy to know.
However lately it feels like there is ond girl who has changed so much.
We used to talk all the time and do stuff together, and now she takes days to answer my texts and I was worried and scared that I might have done something wrong.
And last saturday one of my close friends had a party and this girl attended. I was so scared to see her because I did not know how to react or be around her, and I felt like this the whole night until I had gotten so much to drink that I blacked out and apprently told her how she was not talking to me and answering my texts and calls.
And this I only know because my other friend told me this the next day.
Now im worried about how my friend reacted to this and she is not texting me.
And i have started getting stomach pains and nightmares because I am so nervous and have crazy much anxiety lately