Is it normal that i dont feel emotions for my relatives.

Well let me tell my story first and then my problem. I am the only child of my parents. I'm 19. All my relatives live in different city. So i didn't grow up like the rest of my cousins. I had a very good friend in my school days which I can say is the most intimate friend i ever had. 5 years ago i was admitted in cadet college. It's like the best school in our country so please don't think that i got sent into some military school because i was uncontrollable. Well the problem is that i feel that I dont have deep emotional relationships with my parents or my relatives who loves me soo much. I kinda feel guilty that I dont care about them. I might help them, give a hand here or there but no emotional relationship. My parents hated each other and would argue every 20 minutes when both of them were home. But both loved me very much. But i dont think I particularly love them back. I'm not sure I care for them. I never tried finding or making a girlfriend as i read in a boys school but I'm attracted to them. But I do care for like a.. total stranger, when i see someone suffering in the streets i feel extremely bad for them. And also when i see the suffering of mankind, animals etc. What is wrong with me??? this is weird i think. Oh yeah I've constant mood swings. Like i feel I'm in depression and then i think I dont. I spent too much time on TV, watching Sports, video games, facebook etc.