Why am I so disconnected from my life?

I used to be very ambitious and up beat, the obvious thing now is that I think I'm losing my positive energy. With my friends I don't use initiative but I still communicate with them. After I started smoking, I just feel like I am rivalling the person I once was and nowadays I don't seem bothered or paced, either reluctant or guilty. I feel like a fallen soul, when I play music it doesn't feel like the happiness I made through this, just feels like prodding keys. I play when anyone tells me to play, but other than that, I am closed, and weak/tired. It seems like I never get enough sleep. I know I'm not the only one with this problem, but I know too many before me had suggestions why they are like this. I always feel that there is something to concern about when there's nothing. It's not depression, but it's my identity. Why the big transition? I loved the philosophy of life, but now after being stopped by my parents to have a relationship with a girl, I know what's the point of it? Cheers...