WHY DO WE EXIST....???

The young generation of ours is becoming very vulnerable , recently I got to know about 2 suicidal attempts among my knowns, one was lucky, survived; but the other one was not. He left this world at the age of just 17, leaving loads of of miseries and question marks for his parents. Reasons behind both these attempt to end life were very meager. One scored badly in exams, and other had a heartbreak.

These incidences left me wid many blanks...!!! Are these sufferings severe enough to end one's life??? The level of tolerance of miseries is different for every individual. Some may cope with the stressors upto the acute extent, while some may give up at slightest of pain. Humanatarian and Existential Psychologists say Man should be allowed to use his free will, they reject any kind of determinism from any external factor.
They are free to live, so they should be free to die also. But how many want to die.. its only those who out of depression choose death over living. Otherwise there are uncountable no. of those who are suffering from severest of miseries, but still surviving. Thou all know that Death is inevitable, still everyone wants to keep it at the farthest end, its the ultimate desire to touch infinite.
Where as those who commit/attemt suicide perhaps loose all hope in life. I dont feel that their reasons for such decisions were because that life wasnt worth living for them anymore, rather because they were weaker souls/selfs, who were not able to cope up with, to face the hard core realities n struggles of life as well they were lacking a strong social support system in the face of their family and friends.
Escapism is always easier than meeting challenges. By ending one's life, one gets relieved from his miseries, but leave unanswred questions/never ending problems for his loved ones. Do these people feel that the reason for their living has ended with that one failure, be it of anything.

If so then it leaves me with a question.... what's the purpose of existence? why we are living...? What are the reasons for survival...? These kinda painful incidences keep coming in one's life, so SHALL WE END OUR LIFE.....???