How many people

I study psychology too, and I'm going to start my last year. I didn't know yet to have a disorder when I choose this field. Actually I don't plan to become a therapist (working with sever disorders would be probably too much for me), but I'd like to work with children, for example with learning disabilities, or children that show some signs of problems or are 'at risk'.
I don't know well the difference between Psychology and Social work, because here where I live we don't have this distinction...some people tried to explain me, but I didn't understand well however