You'll be ok. As others have said, its just a test. You can retake it if need be. Figure out what works for you and how you learn best and follow that, regardless of what anyone else tells you.
I cannot learn a lot through MCQs, so for me I don't do them until the VERY end and I only go through them once. Its way more important for me to focus on the material. Some people learn a lot through the MCQs, others really benefit from writing their own notes. Figure out where you fall and go with that. Jeff has his “ninja way” which works for many poeple, but I think many people try to follow something without really thinking about what will work for them.
I have felt really overwhelmed going into every test. Because of my test schedule I could always use an extra day, week etc, but once you walk into the test center you have to totally let go of that. If you're anxious you will make dumb mistakes. As someone else said, if you need to take a minute or two and just “get centered”. I walked into REG completely freaking under prepared and had to chill myself out, then was able to reason my way through much of the test.
If you totally don't know something try to think about it logically instead of panicking. The good thing about accounting is that a lot of the detail is sensible if you understand the “bigger picture”.
I think FAR is the test with the biggest time retraint. Keep yourself on pace, but again don't panic. I think lots of people get frazzled by the sims. Remember that you can use the literature for that. It was less helpful for FAR for me, but once you get to REG and AUD you will be using it more.
Lastly- don't read too much into other peoples test experience. Before I took my first test I was ridiculously afraid of the sims. All of the tests I've taken so far had sims that I would say were really pretty fair. Everyone is an individual and has different perceptions.