And again, i'm unsure.

Unsure if this is what happens everytime? You meet someone, they seem just like you, you share life's stories with them, you laugh with them, promise to be there when things get hard, cry for memories you just made, worry that they're fine, try to work past trivial things, and the big ones too, and just when you think you've found a friend in them,.....BOOM. They become complete strangers.
You forget what its like to laugh with them, you forget that odd feeling that you need to rush and tell them everything thats happening. You find yourself forgetting what your 'special' comfort zone felt like.
What exactly are you supposed to do when this happens? Stay there no matter what and give them a chance to change? Or turn around and never look back again?