What goes wrong?

Why human can change their personality so much just after a couple of time?
Jane who used to smile and laugh everyday, now just left a expressionless face.
No one seems to know what Jane thinking about now.
Even though her close friends.
I can't figure out whether Jane changed, or her friends changed.
They were a group of girls who share secrets to each other and tell all the feeling towards them.
They didn't quarrel before. For the past 4 years.
But then, when a lots of things happened at the same times,
It has the power to changed a person.
Study, Family, Love, and Result just keep on stressing Jane.
She wants to get freedom so badly form this cruel world.
Jane was a hardworking girl, and has leadership.
She was the one who make decision for her friends when they face problems.
Maybe Jane was too perfect in her friend's eyes, so soon her friends will think nothing will let Jane down.
But, it was just too wrong.
When Jane needed help from her friends, she rarely speak out to them.
Of course, her friends won't realize it.
Jane soon become tired, she need to do many many things by herself.
Jane slowly close her heart to her friends, don't tell her friends about anything.
Jane did a lot of weird things to her friends. Things like to a stranger or enemy.
Her friends can't get what she trying to tell them and misunderstand happened.
Now they can't talk happily to each other. Everyone seems like has their own secret in their heart.
Friend A don't trust Friend B anymore. Friend B think Friend A just leaving her further and further.
And slowly, this group gonna break to pieces.
Jane's friends try to talk to her, but she just left with no reply and answer.
Her friends really do hope the best friend relationship between Jane and them will be there forever and ever.
Don't because of own feelings and started leaving each other.
This will just become a joke to THEM. The evil groups.
Jane's friend don't wanna them be like THEM, who act like a best friend to another, but talk about the bad thing behind of the friend.
PLEASE! Don't be like that. =(