I think it was just part of growing up.. those kinds of realizations can throw you into a funky state. The trick is to realize where to channel it... now you know that whatever your goals are in life, you've got to FINISH THEM before you DIE. It's unsettling at first, but I think you will grow into it and it will become pleasant knowing that there's so much you have to do and not much time to do it in.. like when you're at the amusement park and it's closing in a few hours and you have to pick the next two or three rides you want to go on. WHEEEEEEE!!