Hi Celiacheung1985,
I too have difficulty coping in noisy situations - my family know to quieten down when I put my hands to my ears and plead 'sensory overload!'. However, I worked for 16 years as a teacher, initially with hearing impaired young children, and later with pupils who had profound and multiple learning difficulties (up to the age of 19). If you would like to work with children, but find over time that the noise level in classes of younger pupils (I'm thinking below 7 years) remain intolerably loud for your sensitivity threshold, perhaps you could look at working with older pupils or with pupils with special needs (where class sizes are usually smaller, at least they are in the UK).
Hope this helps