There are people you will meet throughout your life, people will come and go, but your true friends are the ones who will stay with you through thick and thin.
It's a natural process in life to weed out your friends and distinguish the meaningful ones from the so-called ones.
If you own a Facebook account, ask yourself, of those people on Facebook, which of those would actually contact you the old-fashioned way if Facebook did not exist?
Who would you be willing to take a bullet for and vice versa? Those are your true friends.