Receiving a job offer in today's competitive environment is an achievement.
Today's corporations have interview guidelines, one of which is to always interview more applicants than they require, then to choose from the most qualified.
This means that not everyone who "passes" their interview will receive a job offer. If you were not one of the lucky few, do not beat yourself up. There are more jobs. Work on your self confidence and make sure you stand out from the crowd next time.
Qualified applicants who stand out from the crowd always end up getting a job offer.
Keep trying !