Study? I can't bring myself to do it

I've worked damn hard so that I can study at Berkeley. Now that I am here, I've no desire to study. I don't know how to explain my lacking motivation in academics. I'm not depressed or anything, but I've just no desire to study. I see no negative or positive consequence to my studying. I've always been into learning for the sake of learning, but I don't even know what I want to learn about right now. My day now just consists of sleeping, eating, playing tennis, working out, and socializing. Occassionally I might go to class and sometimes I read a bit. My best friend says that I'm really just a walking stomach, penis, and mouth. I laughed really hard because in some ways, he's completely right.