Do you mean ur hair is falling out?....It's normal for some hair to fall out when washing or even brushing it, but if it's a lot, then you might want to consult a doctor. And check ur scalp for any bald spots.....If you have long hair, then breakage can occur also and cause it to fall out.
A friend of mine had this problem, but unfortunately, she waited too long to see a doctor. She had a scalp disease, and eventually had to wear a wig. Sometimes it's becuz of a vitamin defficiency. So perhaps only a doctor would know for sure. And stress can cause hair breakage/falling out also. I'd see a doctor right away. Women are so vain when it comes to their hair!