Why do I feel so sad today?

Today is one of those days,
The steady routine of this monotonous life is interrupted by sadness,
In the din of happiness sadness pierces the heart,
I cant understand the reason for it,
Just as I cant understand the reasons for  exuberance on certain days,
My mind knows what to do,
But my heart wont listen,
A lot many memories flood the mind,
The dam of emotions shows a breach,
There is no reason for it,
Maybe some remnants from the past,
Fear of the future,
Or some experiences for today are responsible,
Tomorrow I'll again be the same,
To be confronted with this feeling again...
-Aditya R Venkatesan