Is it normal to have no attachments of any kind to your family?

I respect my mom, she always try to understand me. I have my ambitious first sister she already worked and she always aim at the highest company and ranks(and succeed)and she always plan things out. And second sister she is pretty 'free' she does anything she likes, drinks (sometimes with my first sis), smoking, and a very hilarious person, a make up artist.
And lastly my dad(this guy sometimes violent), in fact because I am the youngest and the only boy he always spoil me, I didn't like it, he always said that my second sis stupid lazy and all (which is wrong cause I am one of the smartest person in my school, and she(2nd sis) still smarter than me)
I always know all of them, but I don't feel any attachment to any, it's possible that if the entire family died leaving me alone, I won't shed a single tears. I have nothing to worry (my grades.. I never even bother to study)(I can get whatever I want with patience)
but I always felt empty. I never cared if god even existed. Am I just some normal guy? I think I am quite different from the rest of my friends.