Welcome.
You are young, smart, educated and free. Even without a strong passion for anything, you are way ahead of most. I have never been a JW, and yet I can identify with the "no fire in the belly" idea to some degree. I, however will share with you and this forum my ultimate goal in life, to die knowing that I contributed to make this world a better place for the next generations. I can't quite bring the passion out, but I do get a sense of satisfaction at the end every day knowing that I gave more than I took. I am 50 and in good health, but the old age, when the "give more than you take" reverses, is inexorably approaching. My immediate goal is to postpone that time for as long as I can. Life may be intrinsically meaningless, and that's the beauty of it, because you get to choose that meaning.