This is normal. I felt the exact same way (and I bet you most others did too). Do things like watching comedy on TV to relax every couple of hours this week, then continue on in your studying. As for test day/day before, here's what I suggest:
- Don't study much (if at all) the day before, just relax for the most part
- Eat a nice, healthy breakfast the day of the test (wonder bread works wonders for me)
- They tell you to be at the test center half an hour early, be there an hour early instead
- Jog around the parking lot of the test center for 10 - 15 min (circulates oxygen to brain), say a prayer, do whatever else you need to in order to relax
- Go in about half an hour early to the test center
- Strike up a conversation with the receptionist or people in the test area, smile - they'll enjoy talking to you, because they're probably nervous as well (or bored for the receptionist) - this will help calm your nerves
- Go in there, make your grids during the 15 min tutorial, relax, and go for it!
It's not too much, but doing a few of things will help you get in a better mindset and get your brain ready to take the test. Don't spend too much time on any one question, just mark it and come back. Be sure to bring a snack for the intermission too. Good luck - you can do this!