Hair falling?!

Is it normal for me to be loosing this much hair on the daily baisis?!
I've been taking Perfectil by Viabiotics for a month which is supposed to help with hair and nail health and growth, and although it did help, my hair is still falling badly. 
I'm afraid I'll go bald at this rate!!
I'm 18 years old, my bmi is 22, I eat well, and I exercise 4 times a week.
What's causing this?!