Is life to be taken that seriously?

Is life to be taken that seriously?

This is a very serious question which haunts me time and again.Always heard saying that what is destined,is destined,what has to happen,will happen.If that is the way ,I must be leading a free life,freedom from all bounds and restraints.Be loony and grin in each moment.I need not have sleepless nights,or to wait for the "damn" declaration of results because,what will happen is already preordained by God,and so I cannot interfere with that.
If I am to think the other way,I land up somewhere else,probably the conclusion is completely flipped.Live Life as if this was the last moment,and every work has to be exuberant.Work till you aren't contorted and follow a path that may even turn a naive into a frenzied fellow.Every moment is admonishing you,an opportunity missed by you has been grabbed by someone else.If others are freaks ,so do I need to be.
If life is to be taken seriously,I should worry about every single second because a predatory beast of prey,known as "competition",has cannibalized care and empathy.Let your soul and body rest in a state of turmoil.  
Taking the life as it comes ,in the long run ,may seem to be a very defeatist and dejected approach,opted by those who failed to compete in the materialistic world to get the larger half of the cake.
Many wise brains say :"Change what you can and to cease worrying about what is beyond our control".But that answers still in a very elusive way and still the question persists  "Is life to be taken that seriously?" 

Life still unexplained??