Good afternoon friends, All days in our life are not same. Some time we feel very bad and some time we are so happy.We also feel that in any day that nothing is working good and we are feeling very sad.Some time we do not know the reason why we are sad but still our mind is not working properly and we feel of not doing anything.This is due to many reasons.In case of girls primary reason is her periods.During this time she is suffering from so many changes in her body and those changes made her sad or angry for small reasons. In case of man it is primarily because of he has some point that is causing her mental tension .

A careful study of man and woman can give us the idea about reason for sadness

source: http://www.bubblews.com/news/7612525-are-you-feeling-sad-with-no-reason