Dunno if you already replaced the shark fin by now; but I had this same thing happen to me shortly after I bought the car. There's nothing in the shark fin itself. It basically just serves as a cover. You can get a new one off EBay if you don't have the original one and just use JB weld to stick it back on there. I did that with mine months ago; and after it cures, it'll survive any kind of weather conditions. Just make sure you don't wash your car and that it's not gonna rain for at least 24hrs once you set it on there. If it weren't dark right now, I'd show you a picture of how mine turned out. For the most part, you can't even tell it had fallen off at any point.