Perhaps you get butterflies in your stomach when you see the bully that picks on you. We all have fears from time to time. That's true no matter how big we are or brave we can be. Fear can even be good for you sometimes and even help you stay healthy. Being a bit on edge can also sharpen your senses and help you perform better in a recital or during a track meet.
Some people even enjoy being a little scared.
That's why they like to watch scary movies - or go on roller coaster rides. For specific medical advice, diagnoses, and treatment, consult your doctor.