being scared is natural. I think that for the most part you have to forget about being scared because it is not productive. Its just a waste of energy. Just do what you got to do and if it works it works, and if it doesnt it doesnt. You can always take it again and again. Some medical school official told me that more and more, they get students that have taken the MCAT up to 5 times.
I understand, but this test is both a test of will and endurance...will to be a physician/go to medical school, and endurance--in the sense that it requires an acute sense of preparation, knowledge of how to tackle the exam and so on and so forth.
I wish you the best. I feel your pain, but you will get there. It is a blessing that this exam is offered this many times a year these days. I mean, honestly, with the twice a year admin, it was like life or death--getting older, having a narrow time frame for preparation (remember when the scores came out in mid-June and August was right around the corner?!!), leaving little time to analyze what went wrong etc.
On a final note, I must say that this exam has a lot to do with simply how you perform on the day of the exam. What I mean is that---you have control up to a certain point, and you just have to accept what happened that day.
Prime example would be being an amature as I was a year ago---nervous on test day to the point where I was not "taking an exam", but rather flying through it. Everything comes with experience and I sure hope that your experience in prepping for/taking this exam will show through in your scores.