How to overcome rejection

How to overcome rejection I just bombed a 30 minute phone interview for a finance summer internship. The interviewer was very polite and gave me feedback to all my answers and said that it shows I did my homework and asked if I had any and questions and he said they were great questions. However, I stuttered a lot and was stuck on so many words. I doubt I got the job or will get a second round. What can I do to feel better and how do I improve? Thank you