Come on look at my experience as new graduate nurse

I am a new grad in new york city, and just lost my first part time job, I haven't start my first part time job orientation yet, and lost it suddenly, my story is " I went to interview, and nurse supervisor said she likes me and want me to work here, then she bring me to the HR and I finished all the paper work, 1 week later, the HR person called me said, they were so sorry, the position they offered to me is given to a internal staff. what a shock. I never heard such thing, why they did that to me, so unreliable. what kind of institution. now I have to start to look for a job again, so discouragement. is anyone here have the same experience as me.