Rejections are a part of life. You will be rejected. A lot of people will not appreciate you. They might even be negative towards you and tell you that you are not good enough.
But,
Do not get disappointed. Move on, look for another company and if that doesn’t work, go for another company. Something will work out. Never give up! Keep believing in yourself.
The more interviews you will give and the more emails you will write, the more experience you will gain which will help you to get better and better.