I'm so scared?

That's really sad. Your brother is sure lucky to have a sister like you, and no matter what life throws at him, he will be okay because he has you. The world can be a lonely place, and people can be so mean, but when you have someone to wipe your tears, to listen to your story, and to care about how you feel, it makes the bad times much better. You have a kind heart, and I'm sure as you grow up, more and more people will see it, and they will adore you. For now, you know your dad loves you, and you know your brother loves you. You've got two people who care about you, you can consider yourself lucky. I know what its like to live in fear. Whenever you find yourself worrying, you've got to tell yourself that whatever happens you will be okay, you will be strong. Don't feel bad for feeling jealous. Just remember that you are the kind of special that people can't see on the outside. You are a natural protector, kind of like a guardian angel, you should be very proud of that.