Teen years IMHO are the sometimes the first signs of anxiety. You have alot ahead of you to think about. What you want your future to be, what colledge to attend, get married or stay single for awhile. These are all normal things but, yes they are things that can cause anxiety. You are faced with some of the biggest decissions in your life right now. Just try and take one step at a time and one issue at a time.
You have a bright life ahead of you if you don't roll them all up into one big event.
Try and relax and put those pieces of the puzzel together piece by piece. You can't just take every piece and jumble them altogether and say it is finished.
You will be just fine. If you feel this problem is getting out of hand, then by all means seek counseling before it gets worse.
Think Positive!