You are already a winner. Even to get an interview means you are doing something right because you were called out of all the other applicants. Disappointments during your job search are likely. Analyze your interview performance. Try to learn from your interview mistakes.
Rejection is part of any job search.
The key is to learn from the process. Tell yourself that not getting this job only means that something better is out there waiting for you. Keep in mind that any interview is preparation for the next interview. Plus, if you made a good impression you may be called back for another job opening. It may help to keep your perspective if you can recognize that interviewing is a game at which you will occasionally lose.