Why am I still smiling when I am not supposed to do so?

Certainly, happiness depends upon ourselves but guess that there is something incorrect with my  
"emotion system"

When there is nothing happen, I will find myself a little bit trouble. I unreasonably tend to be emotional, upset and whatever unpleasant feelings that I compel myself to have. Out of a sudden, I get furious at myself and beloved people around me for no reason.

And, when I encounter from things that let me down or even give me a feeling of giving up, I just force a smile like nothing goes wrong. I keep a blank mind whole day long. Frankly speaking, I do not even seem to be bothered about anything.

What's with me ?

And for God's sake, I cannot control my emotions at all...
Tell me.
Am I abnormal ?