I'm thinking of leaving my job after only 3 weeks of training.
What makes you want to leave so quickly?
I don't like the job and I hate the people.
It's perfectly fine to leave a job if you don't like it or your coworkers. I think you should quit and try to find a job that makes you happy.
You are so right. I will talk to a manager and try to get a paid holiday so that I can find a better job.
That's a responsible way to handle a difficult situation.  I hope you manage to find a new job while on holiday!