I don't feel any attachment to anyone. Everyone is dispensable to me. I can move on really quickly after breakups. I'm fine with losing friends. Even my best friend, were I never to see her again, I'm confident I'd feel nothing. Whatever. I'd move on. I'm tear-free, independent, alone and in general, I just don't give a sh*t. Why am I like this? Why don't I care?
I hope you can get over this - the fact that you wrote this indicates that you want to, and that's the first step. Good luck.
I could be very wrong since I am not a psychologist, and there is very little information about what you're like in a real life, but take a look at this.
http://en.wikipedia.org/wiki/Antisocial_personality_disorder
Your fine you just havent found something worth attaching yourself too, keep searching.
Peace jah bless